but no cold water to dip your buttocks into when they start to blister

somethng else to think about on the rad front, how big are the feed pipes going around the place? if you are spending loads of energy heating big pipes that might be the reason, they should be 15mm to and from the rads, but, from what i can rememebr from back in the day they should also be 15mm going around as well
if you are getting a 22mm feed to all the rads and then it's dropping down you would lose al ot of heat through the flooring

the gas bills are high because you aer running hotter than you need to, but if all your rads are getting hot, but not as hot as they shuold be, the heat has got to be escapy from somewhere

all you have to figure out is where