I had problems with the fuse blowing for a few months, it was a known fault, it was the pressure switch. the diaphram cracks and water leaks through every now and again and cause a short.
I read with interest about the "Flames coming out if the flue pipe"! I think it is the same problem with my boiler. The sound of the boiler starting up is something between a boom and a gun going off.
The BG man has had the gauze and electrode unit apart and there seems to be some deposits on...