Mine had the same problem, flat battery after a couple of weeks.
I suspected it was the boot lid that was not closed properly, so changed the bulbs to LED's just in case it happens again.
Also checked the battery current when the car is locked, it eventually drops down to 80mA if everything is off.
So it you have a 60Ah battery it will be flat in about 30 days, but I would start the car after two weeks just be sure.
Hope this helps.