Thanks for the reply - yes, very painful especially when it was due to terrible packaging from an Ebay seller.
I got a full refund (including shipping costs) so all good but it's a shame as it's in good shape and looks to be great analog scope complete with cursors.
Anyway, only one of the pots is really bad (very difficult to turn) so I'll proceed slowly and see what I can figure out.
The service manual lists the pots as part number:
3142080A
VR Carbon, 16 type, 10KB+50KB with SW
If anyone else has some ideas, feel free to chime in.
Cheers and thanks heaps for all the replies, much appreciated.
Ben