Hotels
Tim, I stayed in a Travel Inn (or was it Travel Lodge?) for the June Exams, 50 quid a night and perfectly adequate. There were 3 of us there and we had transport to drive to the CAA, however, by foot it would most likely take around 20 minutes.
You are quite correct the CAA building is called Aviation House and it is located on the south side of the airfield.
I did have a brochere for that chain of hotels, but I cannot find the bloody thing. I did notice that there were a number of hotels around that area, all pretty much the same. Not sure if the CAA at Gatwick would help in getting precise locations, maybe give them a try?