Hacked a patch out some new 2 mm thick mild steel.
Did it in the evening, the neighbours will not miss that aspect of me.
Not too bad I didn’t think, the camera lense makes it look less concentric than it actually is.
Having done all of the hacking and noisy stuff far away at the garage so as to not upset my direct neighbours or worse still wake the littlun, I retired to the garage for some fettling with the bastard file. I now think that I need to slit the exhaust where the patch will pass through the bracing braket.