Ok follow up on this, took it to the ford garage and like me could not detect any drain. But we then got talking and the mechanic had a theory based on previous cars that have had similar issues. Bluetooth - the bluetooth module in the car remains on as long as your phone is still connected, I park at the side of the house and the phone will often be within connection range. So we disabled bluetooth and in two weeks and counting not had an issue and I wasn't going more than a week or so recently, this is no drain even with all the snow, ice etc. so fingers crossed it is this. BTW. I did test the theory, connected phone to car, opened bonnet, turned car off, left phone in range and left car for 45 mins. Drain was at 0.4 !!!