I glued a ply top to the central baseboard frame at the weekend. That was rather stressful because it was very hot and I had to get glue onto the top edges of the frame and all the ribs and spines as quickly as possible before dropping the big 1440*720 piece of ply precisely on top. In fact I ended up just gluing strategic points and the surface board did not end up as accurately aligned as I would have liked. Hopefully good enough, though...

I have also cut and fixed quarter-circle pieces to provide continuous track bed around the entire circuit now:

The curved pieces are only screwed down so that I can change things in future if I need to. I will probably add further track bed inside the curves at some point.
There's one annoying joint where two bits of the 9mm surface ply seems to be different thicknesses ans so there's a step. I need to look at that.

So I'm getting close to actually laying some track! Not sure If I should bother with cork or not...?

And I'm also wondering if I should start a thread in the "Layouts topics" area. This is never going to be scenic, it's just a dry run for the techniques, to test electronics and DCC settings and to let locos stretch their legs.