I have been with Umbrella Parking for just over 18 months, we decided to pay the extra for under cover parking, they do have another couple of options at different costs, the car is always washed prior to our collecting it, they offer two options either they keep the keys or you take them with you, if you take them with you, you park your car up yourself and keep the keys with you, that way you know 100% that it is under cover.
They pick you up and drop you off at the airport, this has always been hassle free.