I left the car parked up at the airport for a week, came back to it today and it was absolutely dead. Nothing.
Called the recovery guy and it took a set of jump leads plus two battery packs to start it up.
No idea what caused the drained battery. It's only a few months old, Bosch heavy duty. I thought I made sure all interior and exterior lights were off but something must have done it.
When the guy hooked up the cables, this emergency deactivation thing came up. I had to wait 10 minutes for it to count back to zero before it would start.