Thanks for posting, I recently picked up the same mount, with an old 6" reflector at an auction a month or so ago for £45 and am just starting to see how it works and whether it does everything it should. It came with the same tripod as yours as well; I note your tripod cross-support also has rust on it - I was wondering what I should do with that.
Until seeing your post, I wasn't exactly sure what model mine is, however it looks exactly the same as yours, so i assume its a Vixen SP GEM also.
I have stripped the telescope down and cleaned it - it was very dusty (probably sat in a barn/garage for some time. I have also partially disassembled the mount, but won't go too far with it. The RA worm screw shaft is a little bent, so I need to do something with that and it has an RA drive, however I don't have a controller so can't test it.
The mount appears to move well on both axis. Hopefully it will work okay once I reassemble.