Hi Craic, great process description ... certainly made my day!
Just one additional observation: the committee they form to work out head or butt ... its not part of Labour itself. They ask some other people (the unions - who may or may not be sympathetic for the goals of Labour) to help them to find their head ... and if these people actually support some other party, than the returned judgement call might not be that constructive. I think this explains how Cunliffe as well as Little managed to become temporary heads of the said dog :p