META M870 Car Alarm?

I have a META M870 fitted about 5 years ago to a 1987 Jag XJSCV12Cab Auto. It was fitted in Norfolk, I live in Kent so never went back to the supplier. On way home after fitting, the META immobiliser cut the engine and several times after on motorways the same happened. Its been turned off for several years with the override key but when turned on it does activate when the fob button is pressed. The internal light is flashing and the central locking and alarm all function.

Last week after the battery went flat and I recharged it in situ the engine failed to start. I've checked the fuel pump( its running when the ignition is turned half on and the ignition coil has input but no output. The battery is fully charged and fuel is in the supply rack above the injectors.

The auto shift may have an alarm sensor inside the central consol or on the gearbox housing. Twice when the shift is in Park the engine failed to turn over at all but after moving it around the engine turned over but still wont start. Help!!