Hi Maurice,
I am wondering what the flue gas fan looks like, any video or picture on that?
I don't have a photograph of my fan but later today I will find the tool box it is in and take one.
Interesting photographs of your burner in action, you have a good flame combustion wise but the ceramic isn't producing any radiant heat, I haven't seen this happen before. The second photograph with the deflector plate which is certainly producing radiant heat shows a ring of radiation on the ceramic, strange. A thought, do we know that the ceramic that is being used radiates?
I will cogitate on it (doesn't hurt if you are sitting down) until I post the photographs of the fan.
Take care Tony.