[Zelandeth]

Thanks for the input folks, gives me a couple of things to check. I'm 90% certain the line cord it's being used with is the original, but given we moved house four times in 12 months a few years ago anything is possible!

Actually having the schematic will be helpful if I do end up having to do more component level faultfinding.

Also thank you...my brain was utterly refusing to find the term "gravity switch" when I was writing the original post despite spending a good few minutes trying to bring the correct terminology to mind.