I just haven't had the experience of having had to avoid a collision from behind by diving off to the left. Maybe that's to come...
That's what I was wondering. Sure, you check behind before coming to a stop, but if you're just trundling along then either:
a) They have plenty of room for a sensible overtake, so it doesn't matter whether you know they're there
b) They haven't seen you / don't care about your life or their paintwork, and are going to drive into you unless you get out of the way first
c) They don't have room to overtake, so have to wait behind you, with varying degrees of impatience
d) There's room for a dangerous overtake, which you might hope to convert into scenario (a) or (c) by changing your road position
So far I've never experienced (b). I'd argue that scenario (d) can be preempted into (c) by riding in a sufficiently assertive position, unless you're required to keep left by the presence of debris, potholes, etc.