I’ll keep over to the left when there’s a shoulder that’s wide enough to act as a bike lane and there’s no cars parked in that shoulder for a long stretch. And on roads where the lane is extra wide and a car can comfortably pass me at well over 1 metre gap without leaving the lane. If neither of those is true, keeping left really doesn’t help with “sharing the road”, because others can’t overtake safely. The only thing it does if I keep left is to make drivers think they might be able to squeeze past without leaving the lane.
I’ll keep over to the left when there’s a shoulder that’s wide enough to act as a bike lane and there’s no cars parked in that shoulder for a long stretch. And on roads where the lane is extra wide and a car can comfortably pass me at well over 1 metre gap without leaving the lane. If neither of those is true, keeping left really doesn’t help with “sharing the road”, because others can’t overtake safely. The only thing it does if I keep left is to make drivers think they might be able to squeeze past without leaving the lane.