ComJam:
In the end it's a horrific accident that comes down to "see and be seen" not working. Only TCAS and transponding aircraft might have saved the situation.
I don't think you can say that either because you don't know what ATC instructions either aircraft had received. One might have been told "cleared low approach and go around" while the other was told to orbit on base (or whatever). ATC instructions are a vital part of the picture so until we know what those were you can't say it was a failure of see and avoid. Anyone who's flown at Coventry will know that instructions to aircraft in the circuit are many and varied because of the diverse mix of VFR and IFR traffic.
NS