It was a Taylorcraft (G-BREY) and a Pitts Special apparently - it seems one was climbing out and the other was entering the circuit. Seems that it was a simple case of one not seeing the other. I wonder if both being high-winged aircraft one simply climbed into the other. One for the AAIB to resolve unfortunately.
Next flight: Feb 2012 - BHX-CPH-BHX - SK MD87 / CRJ900