Hi all, Ok here goes. Reason for car dead on key was that the immobiliser was activated due to opening the doors using the key. ( Both key fobs inoperative due to suspected flat battery ) .This acivated the keyless alarm system and the immobiliser. There is a keypad in the fusebox on which you can enter the 4 digit code if you have it. I did,nt and the car wont start without it as long as the immobiliser is on. Jump starting the battery and getting running allowed the Fob to switch off the immobilser and I then charged up the battery. I monitored the battery charge over the week and measured alternator voltage with engine running. Battery never dropped below 12,6 v and alternator was 14.4 v .Ie both Ok. I also phoned Subaru garage for 4 digit code. They told me the code is normally on a silver adhesive strip which they had sruck onto the inside page of the service booklet as normal procedure. It was there. Then tried opening door with the keys again to put alarm on and tested that the code worked. It did. So what made the battery go flat so quickly . It was a Panasonic so not the original and a 73 amp one at that. Could still have been over 3 year old though .I did,nt have it load tested which I xhould have but I bought a new one as I cant afford to have a breakdown again. I changed it over using a memory minder which preserved the 12v to the ecu . You Tube a big help ! I bought Yuasa 72 amp as the car has lots of electrical toys. Hope this helps folks.