Roger wrote:
This needs exploring. Not urgently, because hopefully neither of us will encounter a similar situation for a little while

Yeah. I think so too.
There's the argument regarding
legal priority. In the 'simple' circumstances this is well defined, but there are all sorts of shades of grey.
- What if the obstruction is long or even indefinite? This is the case on many residential roads where the habit is to park on one side only. One might pull out to pass the parked cars half a mile before anyone oncoming can be seen.
- What if the width of the road is such that one driver thinks there's still room to pass the oncomer alongside the obstruction but the other driver does not?
- What if the vehicle pulling out judges (correctly or incorrectly) that he can go through first?
- What if the vehicle pulling out correctly judges that he has time to pass, but then is forced to travel much more slowly for some other reason? (Pedestrians?)
- What if the road is single track?
- What is there are white lines or no white lines?
- What if both sides of the road have obstructions (a 'slalom')? How does that affect the priority of the drivers arriving both at the same time in identical circumstances?
Given the dodgy definitions that will apply in many cases as above we also need to consider
good driving practice.
- Good practice requires co-operation. I'd be very happy to give way, even in a case where I might have legal priority if I judged that it would be more efficient to do so.
- Good practice puts safety first. That means allowing as far as possible for errors and misjudgements made by others.
- Good practice means NOT depending on right of way for safety. If someone pulls out on me, I'll make it safe as soon as possible by stopping if necessary.