help needed before the sledgehammer comes out

ok so it happened like this my 94 3.9 v8 disco has been ok till about a week ago when the revo and speedo stopped working plus the battery light was on whilst working after a few miles they started up once home tryed to lock the motor and the fob doesnt work so tryed my spare one no joy a few days later still running fine get back home try the fob maybe 10 times and the doors lock think nothing more till i try to unlock the next day and none of fobs work can still get in via the key but alarm is going and immobiliser wont let me fire it up after much stress and slamming of doors and bonnet find out about the alarm ecu (17vt on this motor) so i unplugged the bugger over night plugged it back in next day and voila fobs work ignition works runs fine big smug grin 4 hrs later try to start her up nothing the fobs still working central locking all that crap turn key and not a sausage just silence now ive been scratching my head all day which im sure has lost some fluff today and cant figure anything out getting it towed to the garage is not a route i want to take any enlightenment would be received with many thanks