The last time this happened was the multi-plug on the ABS unit getting wet. Water settles in the receptacle and so shorts out everything. It was remedied then with another ABS pump.
I have not replaced the ABS yet but thoroughly dried out the plug and receptacle and coated the terminals with switch cleaner, that generally does the job.
However I think the memory is now storing the fault codes (maybe not) but the diagnostic tool I have (AUTEL AL519 ) does not have Rover codes but does show BMW although at the moment not helpful.
I have not as yet had the car on a lift to check underneath - (not sure where to start) but any advice would be gratefully received
Does this mean a more detailed analysis with T4 (Testbook version 4.Computer Diagnostic System)? problem is the car is now SORN'd.
Don't take life so seriously.... it is not permanent! I now have its Granddad ... A 1963 P5 Coupe'