Very simple I'm sure but without any kind of manual I'm stumped! How do you get to the back of the rear ligh cluster on a Weekend to change the bulbs? Can't find any kind of screws or anything but them seem well secured????

Any help would be much appreciated.

I seem to remember that there are a couple of panels that come out from the inside. They have screw caps on and so are hard to see.
If not try a forum search.

the covers that hide the nuts are flipped out with a screwdriver, and the nuts are undernaeth. they are inside the boot approx top and bottom of light cluster.You use the tool from the marea tool kit to undo the nuts. hope this helps.