Electric door mirrors move in the appropriate directions under control of the dash joystick switch until I operate the heated rear window switch. Then left and right operation of the joystick moves the mirrors up and down. Also, I think that the heated rear window doesn't heat. This is difficult to tell as the RR is sooo damp at the moment that I wouldn't expect a fully working HRW to make an impression. FWIW the radio reception is fine. Oh, and when I turn the HRW off the central locking solenoids 'jump'.
Any electrical wizards who wish to make encouraging suggestions are very welcome to do so!
TIA
Richard