I think one of the most serious & perhaps partly overlooked fact on this matter was the fact that this incident took place in the open FIR whilst all aircraft were being operated VFR. When I learnt to fly many years ago, and subsequently in a few instructing years, that meant to me to take note of all traffic information given, and if uncertain of any aircraft's position (when both aircraft reported on final at the same time)ask ATC. They are there to provide you answers. I would be very concerned if I was number two to instrument traffic (albeit now VFR) but pressed on towards my final approach not knowing where the preceding aircraft was. That to me is VERY POOR AIRMANSHIP. Remember the pilots in command are "professional" instructors teaching students to be "professional" pilots. Both aircraft involved were very lucky to say the least.
Radar (if it is ever installed at Kidlington) will only be to monitor traffic in IFR procedures, not to spoonfeed these "professional" instructors around a visual circuit.
Lets hope that this incident will bring home the importance of a good lookout. It could have been extremetly tragic. Remember its not only the number of airliners that are increasing, its also GA traffic. Oxford's ATZ is no more "dangerous" than other busy GA airfields, its the people that are within these traffic patterns that present the most danger not only to themselves, but to everyone around them.
Lets hope that a lot of people can say "I learnt about flying from that".