I've been asked a couple of times now for help with the wiring of the Dan Armstrong (London) sliding pickup guitar. The fact that the low-profile-pickup-sliding-on-a-rail feature was possible because it was also a low impedance pickup meant that, somewhere, there had to be a transformer. And that meant traditional electric guitar wiring schematics weren't much use.
The wiring also included a coil tap, effected by running both ends of the second coil to the back end of the tone pot. With the tone wide open, the second coil was earthed, but as soon the tone darkened, the second coil kicked in.
Because I have no way of knowing which wires are which on the transformer in my Dan, I'm not going to attempt to draw a proper schematic. Instead, I'm just going to draw a picture and provide a bunch of photos. I hope it's useful.