As TG mentioned, in NW Scotland some of the A roads are single lane with passing places. Drivers tend to be much more courteous towards cyclists. I've just ridden a couple of hundred miles up there and vehicles coming in the opposite direction, more often than not, waited for me at passing places. Similarly, I'd allow overtaking by moving into passing places. In one case I recall, I had a heavy lorry behind me and the next passing place was on my right. I signalled to him that I was moving into it so that he could overtake on my left. That allowed him to do so without steering round me or slowing down quite so much as he would have had to do had I waited on the left and made him use the passing place. He showed suitable appreciation.
But fundamentally, I find that the biggest risk to me as a cyclist comes from drivers who misjudge and take risks with overtaking. I ride under the possible misapprehension that no-one is a homicidal maniac and that, even if they are, my riding style won't stop them from killing me if they are determined to do so. Taking the lane at the right time is a vital piece of the armoury of safe riding. Last Wednesday, at around 8.30 a.m., I had just turned right into the Grays Inn Road from Holborn. There were parked vehicles both sides and to have kept one metre from the kerb would have boxed me in. I took the lane. The taxi driver behind hooted and shouted that I was in the middle of the road. After passing a parked vehicle, I moved in and allowed him to overtake. When I caught up at the next lights I couldn't resist leaning into his open window and commenting "You don't know a lot about driving, do you, mate?" which elicited the expected response. The point is, though, he wasn't a homicidal maniac but he was an inconsiderate arsehole. Taking the lane at the right time prevented overtaking, which for him wasn't about speeding up his journey, but about status.