Mr B

Well for it to be the clutch the clutch would have to slip and you would have a VERY sudden increase in revs & should be pretty easy diagnose from drivers seat . From your description doesn't sound like spark plugs either but pulling plugs and looking at the state of them be a smarter move than pulling a clutch without proving it slipping .

One other thing not to overlook on vehicle like this is possibility of an aftermarrket alarm that uses one of its immobiliser circuits to cut the S wire to the solenoid, in that scenario that needs be inspected/tested if S wire power is found be the suspected issue . Even the UK/EU approval requirement alarm upgrade via Sigma had starter cut via S wire . Relays on the Sigma control boards known be problematic at 20 years old .

If you find it works with battery charger connected I would assume it poor connection and voltage drop issue. Could be just coincidence & it always best assume nothing and test everything so the S wire to the starter solenoid wants be proven be always good when key turned to crank . A quick way determine ground side issue is use a jump lead from battery to block ground and test starter function, test the battery terminals for voltage drop first though . You only got 2 + powers to starter, main heavy direct from battery (no relay as the solenoid is the relay) and the solenoid control wire fed from ignition start position . Use a test light and/or DMM to test for poor connection at various connection points, test battery terminals too, don't forget to test both sides of connection terminals/crimp points etc to try determine exact point of voltage drop or perhaps no solemoid control voltage from ignition when turned to crank . Don't forget voltage drop needs be done on a loaded circuit, if you don't really understand voltage drop testing youtube will help teach the basics . A link to a basic starter test principle, same test basics can be used on any electrical connection/circuit with some cognitive thought to find problems . https://www.youtube.com/watch?v=_xvddRJmkAA Once you understand the principles the testing becomes easy & you don't throw new parts at it as you can do diagnosis rather than tryagnosis ...

You could by a hand picked low mileage XT from 2003 to 2008 era for the price of the swing out tire carrier, the wheel and all hidden costs . It would come with a full size spare as they still done things right back then and be 3 times as reliable vs anything newer lol ... Swing out tyre carrier will need declaring to Insurers to save any big drama in a serious claim scenario ...

Well it not likely going be a tooth issue if only happens when hot . You will end up with tooth damage if procrastinate too much and the pinion left to clatter without full engagement to ring gear for too long . What it likely is will be heat soak related to solenoid activation of the pinion gear, whether that mechanical related due to thermal temps or electrical resistance related to thermal temps will need peepers have a visual look for clues and test light/DMM to try gain some insight to narrow down the cause, could even be contact issue at a stud/fixing point elsewhere that getting high resistance/poor contact due to heat soak, again needs peepers on it for visual inspection & see what points in the supply and earth circuit are in a spot subject to heat soak/radiant heat or just look a bit suspect then the test light/DMM to conclude good or fault . Doubt it be too much drama resolve & even if needed replacement new/used starter it not that big an expense (plenty decent used diesel starters available thanks to all the scrapped diesel engines with busted cranks)

If it the linkage rod that snapped you can get replacements of those or make one . In the instance of the pressed metal bracket or pressed metal arms have failed you can re-fabricate these if the rest of the pressed metal not a complete rotted mess. . oem sensors around £100 mark but a repair if it the mechanical linkage related part can be fraction of that . Last SG9 one I remember doing the linkage rod with an aftermarket adjustable one was £20 ... Ideally want pic so can see point of failure and exact sensor type for best part match option .

More modern = more unreliable . From working on this junk daily we see more faults and problems on the newer vehicles, component quality and way it is assembled is a massive decline (and I mean MASSIVE), sure it high tec and comfort but when the electronics/software are cheap/sloppy manufacture and the general assembly is a optimised cost effort you pay the price in constant repair bills and hassle resolving stupid problems/faults . .

B&B will be same as Febi Bilstein just different box . Most of the low to low middle priced stuff is garbage unless you getting likes of old quality stock at reduced price. Some good old stock or genuine/OEM options silly cheap do turn up on eBay. Amayama sometimes is super fair price for genuine part . I would make effort get a Japan mainland made bearing, . If on a budget try go for something with some known reputation .

You got picture of remote fob and the siren . Has the alarm bonnet switch been bent out of position while working on wipers (shouldn't cause exact issues you detailing but best check everything and assume nothing .

flange head style > https://www.ebay.co.uk/itm/335844459486 standard head style that uses a spring washer https://www.ebay.co.uk/itm/335869263703 Can use either or match to what you already got . Worth noting if you buy Delphi ball joints (part number TC959 ) they come supplied with new flange head pinch bolts and are like £10:50 a ball joint on a good deal day . https://www.ebay.co.uk/itm/336390558894

If the current not working keyfob doesn't seem respond during programming the most likely conclusion will be it faulty then you either want send it out to a repair service or buy a used known good one off eBay and program that one then swap the fob board into your key ... Used keyfobs and keyfob repair services can be found on eBay .

You do, it is mounted in dash pull out coin tray near the drivers door (in vicinity of your knee when sat in drivers seat ). You should have a 4 digit pin code that can be used with this keypad to arm/disarm alarm and do some setting and programming tasks.. If you have at least one working remote you can do programming using that remote (you can also use a working remote to program a 4 digit code should you not have one or code you have appears not to work, sometimes original code gets changed by a owner and documented details not updated . ) Before programming remotes I would highly advise you see if any 4 digit pin code you have works with alarm and learn how operate keypad with this code and get some feel for things prior to trying anything such as programming remotes or setting a new pin code . Once you know you have a working pin you could try reprogramming remote but you want be 100% sure battery fitted correct and good before doing that . If you read the attached document fully you will see instructions on using remote for programming rather than pin code and this is procedure that I find easier and more consistent in use . The keypad and beeps/flashes can be a bit funky to get use to for programming so don't expect perfect result first time and be sure educate yourself well before using it and be prepared for some learning to take place during trying to do the process .

see my reply in other thread you posted this in ...

The pictured key is totally normal key see with a Forester SG SG9 with the Sigma M30 alarm . It basically the normal Subaru Key that has a custom housing done by Sigma to house their alarm fob board . You either fitted battery incorrectly damaging battery contact terminals or the board gone bad in process of swapping battery (or already bad prior to battery swap ! ) . You certainly want to recheck the battery fitment but I assume you put battery in it as remote stopped working so is the potential fob fault rather than battery at fault (common for buttons go bad on these) . The instructions for programming remotes is in attached document in this thread . Another good option could be sending your keyfob off to a remote key repair service, this is somewhere in region of 25 to 40 quid . A lot of auto locksmiths won't touch these as that old they got no Sigma interface cable or software or experience on them . Other thing you can do is buy a ussed key same design (easy get off eBay as it nothing uncommon) and put the fob board from that in you Key and program it to your car Sigma alarm .

As mentioned before you can buy a used alarm main unit and plug it in and program your fobs to it and set a new pin code for it if so wished. Only plus with that is remote locking be functional again . Downside is you still dealing with 20 year old european electronics and as it basically can leave you stranded it best pulled out and binned as saves same issue twice (siren board corroded/faulty by leaking P9 battery being super common). I done repairs both ways for customers (option tended to be driven by their preference on alarm and locking). you can add a remote locking system if pull alarm but that adds cost . A working M30 used module is cheapest fix with everything same as owners already use to . You can find used M30 modules pulled from Subarus for around 80 to 150 quid, it must come with pin or a working keypad ( I like a keypad with it as then you got a third keypad that can be used for parts in your key should one of yours fail and it generally easier programming using an existing remote than using pin code) . You got options and none are technically difficult or needs specialist equipment thus the cost to resolve it either way is not crazy money . If you half competent and can google info you could swap alarm module or even bypass it to get running as it really nothing more than cutting and joining some wires ...