Interesting.
Reason I ask is because I was cycling down a local cycle path yesterday keeping left, and met a guy on a MTB keeping right-ish. I moved over tight to the left to give him room, then he moved the same way! I moved back across to the middle to let him through (and avoid a head-on!), and got a 'Don't f***ing move over' from him as he went past.
I think he was just an idiot - he was hammering along on a crowded section making no allowance for peds, dogs etc; but it just set me thinking.
I've always tended to keep left; just wondered what others do. I think these paths are fraught, though, and you have to be (a) aware, (
prepared to make allowances!