Genghis, good point. Although I have only been flying out of Waltham for the last 9 months or so, I have been struck by how smoothly the joining and circuit procedures work, despite the very high level of activity at the field and the proximity of Heathrow, whilst the a/g is run in a very low key way and never pretends to be anything other than a/g. Only once saw a potential nasty when an aircraft which appeared to be operating non-radio carved someone up on final.
This brings me to FFF's point. It does seem surprising that you should not be able to use your discretion to take the runway most favoured by wind, sun position etc, but I suppose that if aircraft are operating non radio, as some of the Waltham aircraft do, then the fact that you have announced to everyone that you are taking runway xx instead of runway yy may not assist the bloke in the non-radio biplane, and neither of you may have seen the other as you position for conflicting approaches.