Car cut out whilst being driven a few times.

Then it was a bit difficult to start and would only run at a really fast
idle speed.

Next it would not start at all.

The fuel injector and coil are not being switched.

The crank sensor, fuel pump, coil, and fuses are all O.K.

The orange imobiliser light on the right haand side of the dash is still
lit up when the engine is being cranked over, (maybe relevant).

The Bosch ECU, black box and key were all  changed but it still will not
start.

Is there a common fault with these cars ? i.e. poor earth or wiring harness
to engine harness connectors.  (these have not been checked yet)

Any ideas please ??