Pop down to your local county batterys, get them to give it a once over for a drain, make sure its charging properly and that the battery isn't duff.
If that all comes back as ok then prob as stated and just not getting enough milage to charge.
Can only echo above, stay well clear of a paddle clutch, twin plates will easily do 500+ if you need to go that far.
Excede or competition clutch rated to the right level will be fine.
whoops lol
In all seriousness, it might be worth just ditching the whole alarm system and getting a new cat 1 fitted, you can get them as low as £300, sack the immobilizer and then can get simple metal keys cut for peanuts.