Roger, if you had given the task of repairing your appliance to this chap, surely you would not now be asking questions here or be out of pocket.
Art of repairing an appliance is a broth made from experience, a little bit of magic and use of tools and instruments to effect a cure. NO ONE can FIX EVERY falut EVERY time but few come very close.
My advice is, stop tinkering with your boiler and let those whose job it is, carry out the alloted task. Thus you may pay a bit more, but you will have reliable job done.[/quo
Ordinarily I would just pay for the job to be done however because my own job involves piping boilers etc and the fact that I knew the pcb was just plugin plus I'd had a diagnostics test done by an expert(he was recommended) I decided his price was too high, hence here we are,the reason I came here was to see if anyone else had come across this same problem