Bugger, my poor memory these days... I think the valve is behind the rear trim near the seat back but maybe it was the B pillar trim... just can't remember.

The reason the pumps are keyed differently is so that rear goes to rear and front to front when you operate the switch. Pretty standard thing when two connectors are side by side however it would be easy enough to swap 'em back if they were wrong so, yeah, not much point