I am suffering exactly the same issue....the 10amp fuse you are on about should be a 30amp though. Mine drains over night if the fuse is left in, I've had it to an auto electrician twice now...the first time I was told it was the radio module in the boot under the spare wheel so I had it repaired but still no joy...the second time he found that the purple/white wire in the multi plug was still pulling 8v after the ignition is off.. when he's tried to find where this goes to all he's been able to find out is that it goes to terminal 15 (where ever the hell that is...lol)...he says he's struggling to find a good wiring diagram for the car....so I'm now trying to find a solution myself have you had anymore luck yourself in finding a cure.