There may be a cd available to purchase. I was lent one by my FI when I was doing my PPL, listened to it on a drive up to Scotland and back again and found it quite useful. It may be produced by Oxford but I can't remember.
Whopity what do you not understand about the following:
In short you can use a scanner to listen to anything broadcast for general reception, radio amateurs, CB, weather and navigation broadcasts. Unless you are a police officer or work in the emergency services you are not allowed to listen to their communications.
You can only listen to other services if you have the permission of the sender. The air show is a good example where the control tower frequencies are publicised and that would be considered permission.
In other words, it is illegal unless you have permission. That comes from OFCOM.
Ian, why don't you ask your FI if it can be arranged for you to sit in the tower and listen for a while?