Yes. A single ball bearing.
After one 2mm across - anyone know where I can get one?

Bike repair shops or engineering suppliers should have them.

http://www.ebay.co.uk/itm/BEARING-O...omain_3&var=&hash=item2ec65a97af

Tried engineering places - only sold actual bearings, and Brammer in Ellesmere Port only sold in 1000's.

Got one from a spare Astra door handle/lock