Appreciate the potential issues with off site valet car parking but used to check the crumb trail; on the GPS in my old Jeep and it was inevitably taken the shortest route from T3 short stay to a compound a couple of miles away so got a bit more relaxed about it. Unfortunately the Audi's GPS doesn't lay a crumb trail.
Do you have a app for your car, used mine to check were the car had been parked when using valet parking at EDI recently