How I wish that I could find a civil airfield that would let me fly a tight circuit,
Try Halfpenny Green (EGBO)
First the CAA policy is for aircraft not to extend downwind because the one in front has. If the one in front has extended downwind beyond the normal point for turning base and remaining within the ATZ then as far as the CAA are concerned they have left the circuit.
This happened to me as a student. Another 152 ahead of me downwind extended a long way beyond the circuit and out of the ATZ so I turned onto base at the usual point and then onto Final and made my call. Shortly after turning onto final the FISO asked which one of us was first (you can't read the registration mark from that distance and were were both mainly white in colour.) The other had turned onto final and hadn't made a call. I said I could see nothing ahead of me so thought I was first and that I thought the other aircraft had flown on elsewhere as it was so far outside the ATZ. It turned out to be another student on a QXC from a different airfield and she decided to go around. I gathered later that the FTO at her airfield teaches them to do enormous circuits - NOT a good idea when visiting an airfield where more normal sized ones are flown.
As it happened, she was so far behind me that I was well clear of the runway and almost back at the parking area when she went around.
