I had the boiler fitted 40+ years ago and it has only ever needed 2 thermocouples hence my reluctance to change it.
I remember a guy sticking a screwdriver in the side of the flue to make a hole for his analyser. His argument being that the draw from the chimney wouldn't let any gas escape.
So if I fill the hole in is it OK?
I was thinking of getting a 1 metre length section of twin wall to fit to the top of the boiler, then connect a 45 degree bend and then a connector to connect to the flexi flue liner ie so most of the flue in the garage is twin wall. Hopefully this will keep any further meter installers happy?
On another subject the 88 year old lady next door had a new boiler fitted by the gas board 5 years ago and also pays for an annual service/callout plan. Last year when it was serviced they frightened her by saying that it was getting a bit old, parts maybe hard to find and she could be left without heating. They said the same about the gas fire in the front room. They made her pay best part of £10,000 for another new boiler and a fire. Then in winter during a cold spell the boiler broke so she rang the gas board and they said they were too busy to take any more calls. I had a look and the condensate pipe was frozen.
This is the reason I try and keep my old reliable boiler going for as long as possible.