AU Falcon, i have a video of it happening but i dont know how to post it up here so i'll guess you will have to take my word for it, but when the car doors are closed the reverse lights come on, not as brightly as if you had selected reverse but they are lit. if you open any car door (except the boot) they go off again and it doesn't matter if the key is in or out or if the car is running or not the reverse lights stay in a lit state until you open one of the car doors.

any ideas in the slightest?

have you crushed some wiring somewhere?

thats what i thought aswel or maby some water got into some wiriing since this started just after a massive down pour, but i decided to take some of my own advice and the was "to fix the cheapest thing first" which happened to be the cheap Chinese LED bulbs i had installed and as it turns out that was the problem! (circuitry in the cheap Chinese bulbs fried themselves)