[CambridgeWorks]

I seem to recall the plessey round power plug used was 6 pole, not 8. Maybe a typo from Roger??
The diagrams from Martin are for the "ordinary" dash or boot Westminster, not the motorbike. This is in line with what G6Tanuki said, referring to the small rectangular plugs with a grey mottled plastic coating over the aluminium cover.
To sum up, I imagine what Roger gives as connections looks quite likely, just the use of "7" instead of "6"
Rob