Since I've had it, but the seats had been swapped around a few times when I fished the history..
Today swapped my Phase 1 RS Seats onto Phase 2 DCi bases (without airbags and easily access to the rear seats with the higher lift forward handle), now matchs the Cup wiring (non airbag), wired up and made good all connections, resistors in the missing black plugs, the seat belt warning light now works and beeps when you pull away until you belt up, so the wiring for that must be ok, but the airbag light remains.. could be anything now but my money was the seats as the wiring was a mess and mostly not connected. Need to plug it in, clear all codes, then see what appears I guess