I have an E46 coupe, which I can easily fit 1200 x 1800mm sheets of plasterboard in. I need to carry 2 doors of 1980mm- so there is an overhang (approx 100mm beyond the bumper edge) and the tailgate won't close fully. Obviously I have the anchor points (in the boot space, and the forward seatbelt floor anchors) to stop the doors sliding backwards using rope and bungee cords.

Am I allowed to drive like this and are there any restrictions beyond normal road controls?

I ask as the highway code, section 98 states "you MUST secure your load and it MUST NOT stick out dangerously." however various forums suggest it is ok up to 400mm providing there is a red cover to alert anybody behind.