I've finally found the correct Klaxon (actually it wasn't - but I thought it was at the time!). Not all that much left to find now!
Well a lot to find really, but not that much more that's difficult to find. I'll pick the easy stuff up as and when I need it.
I'm now following up a lot of leads on the really difficult stuff too. It all takes time, finding someone who has a part you need, then persuading them to part with it, often by finding something they need as a swap. Otherwise these parts will have to be made.