Still not happy with the smell from the heater so, for peace of mind, there was only one way I could go; pull it apart.
After removing the combustion chamber and finding it relatively clean it was time to look for the next suspect.
As you can see, no problem there.
Same again. Only one thing left, which I originally thought could be the problem.
This little hole blocked but, in this case, clean as a whistle.
Removed the gauze just to make sure but, as with my previous findings, waste of time.
The only thing that I can find that has any difference; one of the ends is flat (which was the original) and the other end is chamfered, which is what I replaced when I pulled it apart last time.
I am completely stumped so I will rebuild it and continue using it and, hopefully, I will find the answer.
Rae