Hello all again, hopefully this will be tha last you will hear about
this from me! The nice guy came to fix it today, seems it was a
slightly dodgy non return value in the fuel line to the pump that was
the culprit. Now bearing in mind the system has only been in what? 8
months? I would have figured it lasting longer than that before going
tits up... either way it wasnt the ex, but has made me much more aware
of securing the bloody thing in future so he CANT do such stuff as he's
a sneaky bugger!! and it may in the future need this valve replaced but
seems giving it a bloody good hiding has cured it at the moment (oh the
joys of air locks eh?)
so thanks for all your help, and if in future I ever need to troll my
system i have facts!

not cold, in fact toasty babybanks who should turn the bloody thing
down but is making the most of it for a while