Happy to say that the speaker is no longer rubbing. I managed to partially remove the dust cap and gave it the business end of an appropriately vintage Hoover Constellation. There was no obvious corrosion or particles to be seen, even with a good light and a magnifier, but I suppose with the tiny clearance between coil and magnet, it doesn't take much.
Anyway, thanks again for the suggestions. All is sounding good and I can now reassemble the record player, ready for a 'Success Story'.
Steve
