......cymbals!
Disconnected pipe 22 at the master with the rear end off the ground, slackened bleed nipple on rear right, assistant pressed brake and nothing at caliper end. Plenty fluid on the cloth under the bonnet though. Connected all back up again, fitted my new calipers all round and bled the whole system. A bit more peace of mind now. Turns out they had been connected correct way round but I had to check. The brakes are no longer pulling too. Thanks to all who made suggestions esp Dave4x4 who came up with the pipe ID numbering. Which one is which for the front, do you know? (just as a matter of interest)