Forget using your intruder system for your fire alarm, its not a recognized method here in the uk.
Buy some proper mains interlinked smoke alarms, they will probably save your life unlike the system wired in alarm cable.
I would indeed question that statement, as its always been required to have calibrated equipment and has been for donkeys. There was a time they wanted regular self-cal as you have said with a yearly cert as well but that went down like a lead balloon and was scraped (still have logs somewhere). But as you may know the NIC make up what ever they want
That's always been the way
On your metal back box, the two screw holes one is normally fixed and the other moves so you can level your accessory front (socket).
But not always and you can have insulated ones and two that are lose.
Its not a requirement to earth the back box if you have a back box with a fixed lug.
Other side note
fatallyflawed.org.uk
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