Rod,
Two different inspectors at two different clubs have actually picked my boiler up and had a quick look at it. They did not perform a thorough visual inspection or a test of course. Both of them seemed very approachable, helpful and suggested that the way forwards would be to start with a pressure test. Both clubs were a long way from being frosty. However, life got in the way a bit and I have not returned yet. Also, I have since discovered the various issues that they might not have noticed or appreciated with their quick look. Such as the lack of longitudinal stay bushes, the regulator bush and the 3/4" spacing of the side stays on 1/16" sheet. Also, the lack of a top water gauge fitting.
In defence of the boiler as it is, it was built in accordance with the drawings and construction manual that I had at the time and I suspect the staged visual inspections have been introduced since say 1985.
One reason for posting this thread was to check whether there were any other weaknesses that I should make sure the inspector sees and whether there might be any elegant solutions to the weaknesses.
Interesting to note that you had problems with the cyclone burner. I don't have one but I was relying on that type of burner to help if I had similar firebox issues.
Phil H