An update with some recent photos (of limited quality). I've just finished tracklaying on the scenic board, although testing and tweaking is still in progress.
The photo below gives an idea of the underside of the board. Dropper wires from each section of rail have been attached, but I've yet to connect all of these up. I've also installed functional tie-bars beneath each of the four turnouts. These still need to have servo motors attached - some experimenting is necessary with springing and microswitches.
Close up of one of the functional tie-bars on the workbench:
These essentially follow Geoff Jones' design in the Track book. The blades themselves are attached to cut down 12BA bolts which sit in the tubes you see here.