Bert Coules wrote:

Thanks for that. The US Stanley site does have something which looks very
like the gear I used, though without the edge-stiffeners for the door
panels; but despite several Google searches I can't find a UK presence for
the company.

Well I read "ACMETRACK" from the sticker on the back of some pre-made
sliding mirror doors, IIRC bought from Smith's Do It All, but a good few
years ago ...

Surely there must be one?

Looks like there might be a handful
http://www.google.com/search?&q=acmetrack%20site:uk