> although FWIW most of the time I don't feel the need to occupy the whole lane.

Yeah, I perhaps should have made it clear that occupying a full lane is something I do probably <2% of the time. Not very often, and for similar reasons to the rest of the comment: I don't really want to have to deal with cars, and if I can stay right and let them by, I will.

I'm in America, so it depends on the road; where we have unprotected bike lanes, then I'm in that & there's passing room, but too often there are "sharrows" where there really isn't a good deal of room for passing. Then it's very situational. (Usually the car taking up part of an oncoming lane as they pass.)

In the UK you're not only allowed to take the whole lane, the Department for Transport (through Bikeability) calls this the primary road position for cyclists. The guidance is that this should be the default, with the secondary position (~1m to the left) only used when the road is wide and the rider is certain that keeping to the left wouldn't compromise their safety.

https://www.britishcycling.org.uk/cycletraining/article/ct20...

I go into roundabouts while occupying a full lane, unless I use the first exit/turn left.