I was shocked to, nothing on the flu or at least he never said anything and he only looked at the flu to ensure it was connected. Got hold of the gent I had hoped to get to come but he was unable to come so still looking for someone else now. He suspected it would be heat exchanger or pcb fault also, but without checking none the wiser. I am pretty dissapointed with Ideal, but they did call and offer a direct discounted boiler supplied direct but not a fitting service, I may take that option or elect for another make, depends on costs and if I can find someone local to fit, they all want to supply and fit i guess. So have to find a fitting cost option to make my mind up, unless I find another engineer to fix, apparently the heat ex are costly parts, so boiler option may be the way to go.