I have been having intermittent ignition lockout on baxi solo 30 he.It started 6 months ago once or twice every few days.It then didnt fail for 3 months but is now doing it up to 3 times a day but not every day.Have cleaned condensate trap .I am worried an engineer would come and change something that would fire up ok but fail again in a day or two .Any ideas on what it might be or what it definitely cant be because somedays its ok.