I have a mixed 1-pipe and 2-pipe central heating system. The 2-pipe
circuit feeds 2 radiators added by a previous owner. It has been
difficult to balance as the 1-pipe circuit hogs all the flow. I have
now added a balancing valve to the entire 1-pipe system which seems to
do the trick. I only had a 22mm compression service valve to hand,
and it is not the best type of valve to make delicate adjustments.

My question is, what sort of valve should I be using to balance a
domestic heating system? I have found double regulating valves in a
web search which look just right, but at over 100 pounds for a 22mm
compression valve they are far too expensive for domestic central
heating.

MJA