Many thanks to Mark for coming out and diagnosing the car, getting an ECU Rejected fault relating to the EWS. The weird thing is that we can talk to the ECU and EWS so we're hoping it's still some loose cabling or faulty fuse, going to be a while checking I think.

We also ruled out the Autobox's lock so it's not the switch in that.

Battery was down to around 5.8V when it should be at 12.7/8V for starting.......