I think that pilot error was what most people thought,even very early on it seemded like the most likely cause.
He started his loop manoeuvre too low,didn`t get the required altitude to safely complete it,and the aircraft was doomed to crash.
I wouldn`t be so sure the CAA will lift all the restrictions-I get the feeling there are elements in the CAA that would rather not have ex-mil jets flying in the UK,especially in civvie hands.