Thanks for that. It's all slowly starting to make sense!
So, no flying in class A. Class D is possible with ATC permission, treat MATZ like class D and TMZ should need a transponder, but the stansted one is possible to fly in without a transponder if permission is given, just like class D.
And anything class E and onwards doesn't need a transponder. No class B in the UK, and god knows where there is class C, but its nowhere near where I am!
Is that all correct?
Ta. IPZ