Nosticks - the dash pulled off easily and was able to remove 4 screws holding bezel to dash, slide the Axxera out partway and remove the other 4 side screws holding the bezel to the radio.
Did pull tests on all wiring - all wires passed - eventually found that the reverse switch has been misfired to the Axxera SW1 input for the steering wheel control. Cut the wire and the Axxera touch screen functionality and all the menu screens returned. Connected the reverse switch to the reverse wire input and the camera screen switched on - everything is working again and Iím a happy camper once more!
Thanks again for your vital info!