Hi
The wiring had been cut and joined in multiple places, and replaced with bits of all colours, including from the CB itself.
I printed out the wiring diagram in your C5 cct thread and traced everything from the CB itself, worked out which wires were meant to be which colours, and connected it as it should be in the instructions (albeit to some very random wiring colours).
My C5 really needs the wiring stripping out and redoing, but it's not a job for a small back yard in the middle of a very wet autumn
I did find an accessible +12v and 0v though, via pins 3 and 5 of the pod loom connector - I've fixed my voltage meter to that now.
Hope that helps!