Relays, if not where Dave W suggested, try up behind the glove box on the passenger side.
To me, it sounds as if an immobiliser isn't passing a 'Go' signal to the ECU.
Cheers,
I'll adopt the pose and have a look behind the glove box, I haven't looked there. That's where my ECU is mounted but it could be above it.
As for the immobiliser GO signal, that was my first though too, it makes sense as that's what an immobiliser does. However, I think I've established that there is now none fitted and I'm looking for a basic vehicle wiring/relay/fuse fault.
I have yet to locate the relays for the headlights and indicators, and the main power hold relay. This is my next task.