definitely the valve thats gone
Gaz, thats a heck of a technique for fault 'diagnosis' you have there, would you like to be on call on my behalf?, because you could accurately diagnose what I have to book a visit to see with my own eyes/nose/electrical 'light-up' screwdriver?.
Do you use clairvoyance, x-ray vision, expert reading between the lines, sixth-sense or what?, I have been thinking of going on the Mrs.Combi course, it has had such good reviews in the CC, but am beginning to wonder if there's a better way?
Its amazed me that the OP just accepts what you have said as 'gospel' too.
Nice one.
DH