Out of curiosity I went on the Stansted website and it looks like they aren't taking any bookings for fast track at your times on Saturday (23rd right?) so it seems to be a moot question.
Ah! You are correct, I hadn't even gotten that far.
It is now double moot, as Widero has further moved the flight to Southend Airport. Oof! Anyone with experience here lately on security times?
Thanks all