Maybe a long shot but........

[Badger]

Did the job , sonically cleaned it, assembled it with a smear of graphite grease where necessary and it's back perfectly.

If anyone else is contemplating the same job, then might I suggest taking notes regarding the stripping/assembling the compound lenses to enseue correct reassembly.

BIG thanks to all concerned

Sounds like it would make for a great topic for a Knowledge Library article ...

Regards,
Badger