Spent lunchtime today cutting the little fluted bits in the dropouts. Not a spectacular amount of progress, but it's details like this that make the difference.
The dropouts are now glued on and the rear triangle feels loads more solid for it.
I've started thinking probably hubs next, and headset. I quite fancy the idea of getting the wheels in and having a "rolling chassis" to hang the rest of the bits on as the build progresses. Maybe a scale workstand is required...