Good news, and these parts are not so expensive. I normally carry a spare amplifier, my theory is that when I am out of the UK it can be more difficult to find parts, so I have a stock of small items. A few years ago we visited the Land Rover agent in Berlin looking for a fuel injector for one of our Plus 8s. We had a very nice coffee, toilets were extremely good, but the staff seem to be born after the Rover V8 stopped production, so they had nice suits, but no idea what engine we were talking about.
Getting bits for the crossflow became like that at Ford dealers. I can't remember what I was after the last time I went which was many years ago, but the guy didn't have a clue what I was on about. The guys at the factory are still very helpful (and their jobs are much more complex nowadays) but I used to enjoy the pre-computer days when the stores were on the other side of the road from where they are now: you used to ask for something and the old guy who ran it would walk straight to the correct wooden cubby hole and come back with the right bit.