There's extra wiring on the passenger seat I believe for the sensor that says if the seat is occupied, I don't think the drivers side has this as I guess it's assumed if the car is moving then there's a driver in the seat, so LHD passenger seat won't be a direct fitment for a RHD drivers electrically.
I was considering buying some seats myself from Germany but got lucky with a pair in the UK just before Xmas that's how I found this out.