Well, I found the 2.5mm drill and all the top-hat bearings!

A comment on glues: I used a PVA-type glue called "weldbond" for the timber underframe, and I used araldite (a 2-part epoxy resin) to glue the whitemetal axleguards to the frames.

The holes for the coupling hooks were made by drilling two 1.0 or 1.5mm holes and then using a sharp craft knife to make them into a slot. A little more work with the craft knife and the hooks fit in perfectly. The springs are somewhat superfluous, as the hooks are a tight friction fit into the buffer beams.

So I now have a rolling chassis! When I've finally figured out what wagon is going onto it, I'll sort out the brake gear, but I'm likely just to use some bits from a huge pack of whitemetal castings I bought several years ago. When I've sorted out what buffers I'm going to use, I'll add the remaining underframe timbers.