The Rover V8 and all the associated electrics and electronics are normally pretty reliable and any issue can usually be traced to poor electrical connections, normally I start with the earths , but then work my way through the loom.
After many years of vibration it is perhaps understandable that the simple spade connectors start working loose. Modern vehicle electrics uses multiple plc controllers and very thin gauge wiring with more secure connectors (as a rule, not everywhere!)
Glad you are sorted
