A spare Moulton series 1 fork turned up, so I stripped it down for parts. Nylon bushes very good, small parts very good, bellows junk (boo!). Low mileage, heavy neglect. I am going to try some Bilstein steering bellows from a car, which are the right inner diameter but a fair bit longer, with an extra two ribs. As long as they don't bottom out, they'll work.
Put the main fork and steerer back on the Bay. The crown race is really nice so it should be a useful spare for someone.