Well I'm not gonna mention the schools but I will the Airfield.
1) Elstree ATC, the most unfriendly and uptight bunch of controllers I have ever had the displeasure of being on a frequency with. They thing they are Gods gift but very far from it.
2)The Runway. Ok it's short, which is good practice. But check out the surface of it. Full of pot holes and ruts. Probably the worse runway I've ever landed on. Infact some Grass runways are smoother.
3)The circuit. When you are with a student, it's nice for them to get used to a circuit pattern. If you are circuiting to the North there are 3 different patterns. Outer, Middle and Inner. How confusing is that for new students.
There are other bits but I wont go into anymore. But think of the senario of Take off on a bad runway surface, trying to work out which circuit pattern to fly around and speaking to unhelpful ATC that actually allow joining traffic prority. Then land on a badly surfaced runway, It's a joke.
Go somewhere else.
Denham, Wycombe, Stableford are much better choices.
Good luck