I'm only half awake - first thing Monday morning! I'm trying to visualise cutting out all the bits of the British Isles on thick card, then sticking them in their correct relative positions on a circle of card, then doing the dangly line drawing thing to find the centre. Does that get over Greg's problem of weightless struts? I'm sure someone will soon shoot me down in flames, but I can take it - my penalty for being too idle to really do the experiment!