Well I'm going to presume that there are "right of way" regulations in the UK, as we have in Canada, and the US. Obvioulsy, they should be adhered to as best as possible. Generally, in Canada "right" is the right answer in terms of who has the right of way, and which way to go in case of head on conflict.
I concede that in a nation where the cars are driven in the other direction on the road, it could bring about this question for a North American trained pilot. I'm sure someone will be along to remind me that it is us in North America and continental Europe who drive on the wrong side, and what is to be done in the UK.
I think that right of way rules are based to some degree on the seat normally occupied by the pilot, and surprise surprise, it seems to be left seat by convention for planes just about the world over - a lot like the cars which are build the right way across
. I would think therefore that the logic of right of way as it related to visibiliy, would be the same in the UK as the US, but know the rules locally.
If you maintain good awareness of what's going on around you, the risk of mid air is happily low. This can be managed with good airmanship.
Fly with good awareness, and worry less....