Change colour and move on Ian. You have had a bad time and I wish you luck with the next one, I am really glad that you remain upbeat and still like the car.
PM sent which I hope will help a little bit.
Afraid the skipping Bose is something that cannot be rectified. Most change out the unit and upgrade to something designed after the 70s. Have a search through the ICE section and there are quite a few upgrade ideas in there.
I have the non GT Clarion so am ok