thanks jim youre a diamond,i have however finally sorted it out!!i took it to prochem to service it,i told them i descaled ,they asked if i cleaned the chemical check valve and the solution screen! needless to say i didnt (how am i suppost to know?) i used it today it was perfect,i asked them why dont they have that info in the manual?
when things go wrong thats when you learn how the thing works
they gave me a tip on how to clean the solutions hoses which may have helped as well,put half a litre of fibre and fab in the header tank, run it through the hoses and leave in for an hour then flush through aparently they clean machines with it and everything
so thanks to everyone who contributed to my problem
gary