I have a 500EL/M with this problem. I acquired it as such, and I figure it was most likely a dead battery in the body that stopped it from cocking properly.
Thanks for the link to the tool, I've been eyeing it for ages, but am too scared to dig around in there with a screwdriver! $20 to salvage a Zeiss lens that hasn't been used in years. Done.
I had a lens that was "fired" but was off a body and couldn't be reattached. I cranked it back into the correct position, but the amount of rotation made me wary of trying it on the EL/M---I wasn't sure I could securely hold the body/screwdriver while turning it so far.
EDIT: Totally missed pg.2 of the thread (Woops). Sounds like a bigger issue than just cranking the mechanism. Hope you can get it fixed for less than 250 quid!