Hi Old Jud,
Whilst I can't help directly with spares suppliers usually I would of said Rus milliatry.
If you haven't already have you checked out the UBC in the the mak forum?
Plenty of advice and seal fitting etc.
These might help:
http://umarexboysclubforum.myfinefor...p?f=64&t=22289
http://umarexboysclubforum.myfinefor...forum.php?f=64