Mk2 rear wheel bearing size?

I've a roadtrip coming up in the GTI and one of the rear wheel bearings has some play, even when adjusted. Anyone able to give me the size? Local dealer wouldn't have them, and I've access to loads of bearings in a machine shop.

 

Meant to add, it's the smaller, outer one.

 

The MK2 GTI rear bearing kits are common parts in GSF and Euro Car parts. Never measured them, although I might have a set somewhere outside. Might take a while to get to them though.