I removed the highline radio to get at the steering controls interface box that connects the steering controls to the radio.

I didn’t expect to find a load of extras wiring and several boxes of electronics to come out as well. After some investigation they are all parts of the radio telephone that was installed in the car when new. The hand set subsequently removed I guess when MG Rover sold it 2006.
The interface box is the small white box seen still in the dash in the photo. I swopped it for a replacement but still the controls don’t work.
Next stop the rotary coupler under the steering wheel!!