Easiest way to check what the prob is;;;;
Get a good ameter, remove -ve wires from battery bolt them together, then connect meter in series one end on batt other on wires, DO NOT start car etc..
you will se a draw figure (might be best to sit in car or remove door pin swtich)
it may be as high as 0.2 amps IIRC, till the inerior light relay cuts out after 20 secs or so it should drop quite a bit
I cant remember exactly what mine was, but I THINK it needs to be nearly as low as 0.020 amps
anyway whatever it is, in idle state, one by one remove each fuse in the fuse box/boot area, when you pull one and the current DROPS significantly, THAT is your problem circuit... I found mine to be an OLD tracker battery, which was no longer in use but still connnected!!