Do you think that could stop the drain? Hopefully that is the only thing that would be drawing power with the ignition left on?

No, not changed anything since I bough the car about 6 months ago now, it has been fine up to recently.

So not sure what's changed, probably a loose connection or something shorting somewhere?

God knows how its all been wired up, was done by the previous owner and I know the wiring is a bit dodgey, some of the interior lights come on and off such as the cabin light and the light behind the heater controls.

Maybe this could be related too?

Also one of my side lights and a brake light is out, could that maybe be related too?