right the hose is not the cause of the leak, but digging around with some virgin snow at my folks has identified it is not dripping while idle or reved without major load going through the system.....
there are crystals that are being formed on the waterpump, so a leak is happening externally... which is good, but i can't see it dripping at idle etc... frustrating but better than it going internally!
pressure pipe is being made up this week, and i hope to get my hands on it and try to get some holes drilled and sorted over Xmas period.... but it may not be done before i leave on the 23rd, so might be closer to new year....
Decided in the rework to get the pigtail of copper attached directly onto it my by mate, as it saves me trying to faff about with it and cocking it all up