I've now had the whole unit out again and blasted the selector knob unit with Air Mass electrical cleaner.

This has stoppped the erratic selections but now nothing happens when pressing the knob to make a selection.

The radio is stuck on the FM frequency band and all selections on the radio control panel are not working. Only the volume control works but the radio cannot be switched off when pressing the radio knob.

The Menu button is not working so i'm unable to get back from radio display to computer or sat nav display. Radio stations on selected FM Band can be selected on the steering wheel selector.

All these problems may be related to the computer selector knob not making correct contacs, but not sure.

Any help or technical input to this problem would be much appreciated!! Otherwise here i come Ebay!!