Thanks for the link andy.

will probally do the 1st choice as i'll do all 3 and work back to the
22mm then.

Now as the run of the 15mm goes straight across the 22mm and feeds 6
rads, would it be better to cut the one feeding 4 rads on it's on run
to be sure.

Is there a rule how many times i can cut into 22mm pipe? the pipe is
only about 2m long.