Thanks guys for the replies, I've disconnected and reconnected all the relevant ones in the boot, nothing. I'm sure that these aren't individual faults, but actually all related. Rear Sunshade, SatNav, Tail Lights, Stop Lights, Reverse Light, A/C, Heated Seats, Fuel Door Opener, Fuel Gauge. Do these have anything in common as far as relays and such?
The SatNav I couldn't care less about Phil, it's the tail lights, reverse light and stop lights that prevent me from the car's last MOT. 🙄