Flashy lights
Stu I would agree with LandRover but when are the lights flashing on/off. Is it with ignition off, key out and door open? is it when you open the drivers door only or does it happen on any of the other doors (on thier own) ? is it the front internal light or the rear passenger lights? do the boot and door opening lights flash as well? Sorry for all the questions.
Things to possibly consider/do:
Try each door individually....if it happens on just one door in particular, do as landrover suggests and grab the cable loom that jumps across hinge side and give a sqeeze....do the lights stay on/do they go off altogether/does the flashing change. If so its a damaged cable in this area.
If the cable loom squeezing doesnt have any effect, have a look at the door contact switches. I found my kids had a knack of kicking the rear door switches which are located on the wheel arch section of the door shut. If not visibly damaged give them a squirt of WD40 and exercise them.
Hope this is of some
help.
BTW I know Haynes dont do a manual for the Mk2 Alham but I managed to get one on ebay called 'Pocket Mechanic Vehicle manual' by Peter Russek. There are electrical diagrams included but as usual are not very clear but do give some good info.