Observations on the recently opened Cycleway 4 in South London indicate that 25% of cyclists choose NOT to use it in the contraflow direction. This is consistent with the view of many cyclists that it is better to be on the "correct" side of the road.  A short report of the counts on CW4 is at

https://drive.google.com/file/d/1RONkTFVNwjOZgjpeTdxw_W06R08d9h9_/view?usp=sharing

I would be interested if anyone else has similar findings. and in general how people feel about 2-way tracks.  TfL seem to like them (use a bit less space, a little cheaper). But if they are significantly less likely to be used than two 1-way tracks, this information might get us better designs.