@SugarBaby this was perfect - thank you so much. I can't believe it was something so simple. I've loosened them as much as I dare, and it's working much better now. It's a bit iffy at the extreme...

Hi I originally installed this switch quite some time ago (maybe 18 months or so?), and although it wouldn't fit the back box properly, the long screws held it well enough to be stable, and the...