Well, I attacked the damn thing with a dremel this arvo - seriously!
OK, not quite that bad. I polished up the pins using a dremel & polishing pad and it seems to be on the improve. I was a bit fearful, though, as after I had finished the job, it wasn't working properly at all. I then played with the T switch and it came good. I have just done an aproximate test using my DSLR in the focal plaen and a light source to test the shutter speeds and they look pretty close. From my eyes, I think @ 1/500, its a small bit slow - maybe around 1/400th.
I'll run a roll through it during the week and see how they turn out.
Cheers