I was thinking my 40 year old Suntour Cyclone Mk2 GT needs its jockey wheels updated, spotted this for £10 on Amazon
Sealed bearings and the same diameter as my spare Suntour VX jockeys (33/38 mm)
Comes with 4 sets of adapter shims, one of which will just take the VX GT through bolt (6mm).
However they are about 0.85 - 1.0 mm thinner than the original jockeys so I may have to get some shim washers.
Edit: Added for searching - BBB Rollerboys BDP-01