thanks guys, i'll check them out.
although now i've just had a closer look, seems I must have torn the extremely thin wire out of the solenoid at some point today, if I can't solder that back together then it'll be stuck at 1/500s (I'm an absolute gun at microscopic soldering, it's just a matter of finding the other loose end in the coil and not melting it, I know how hard those things are to fix).
Maybe this entire thing's just a write off anyway...