I went to Amazon, and found a Spanish-keycap Unicomp keyboard for only £12. That's a ridiculous price, so I bought one. The keycaps are all Spanish, so I'll have to replace a dozen or two of them, but since I have all these faulty keyboards, I can cannibalise those. I'm just hoping that this is a bucking spring keyboard.
I also found the exact Unicomp keyboard that I like, from a UK company, which means postage is free, I won't have to worry about import duties, and I can reclaim the VAT, so it'll only cost me £107.50. So I bought one of those also. I got it with a USB interface, because that seems to be the way that keyboards are going.