[I thought it would be useful to summarise this discussion and remove it from the (largely unrelated) thread in which it originated.]
Let me begin by saying that I find both of your contributions interesting and valuable, and they have provided some insight for me into an area (in both senses of the word) I hadn't really given much thought to. And anyway #geographygalorerulesok.
However, I think you are possibly overlooking the meaning and purpose of the areas on Pubs Galore. The name for this feature is "served areas". I take that to mean that a pub that is just outside the area (as a geographical entity) can serve the area even if all the people who drink in the pub disagree. It would need a serious barrier, like a river or a railway track without bridges or underpasses, I suggest. I remember a similar discussion a few years ago when I seriously annoyed Conrad about an area in York that was split by the railway. In those sorts of cases it may be useful to think about what the parish or ward boundaries are, but in general it's not.
Here's an example: in London, a lot of the areas that have been developed on the site are based around tube stations. A lot of the time that makes sense: in an intensely developed urban area, the tube station is a landmark that people refer to. But the further you get from a tube station that acts as the centre of one of our areas, the nearer you're going to be to another tube station. There comes a point where a pub is within a reasonable walking distance of two (or possibly more) tube stations. In Birmingham it makes sense that the area near the railway station and tram stop called Jewellery Quarter is called Jewellery Quarter, whether or not a tourist leaflet defines it the same way. Similarly, and without knowing the first thing about the canal in Birmingham, is it really such a barrier as is suggested by Richard's points b) and c)? Maybe it looks like a convenient line on the map, but in reality?
Interested to hear your thoughts on this. And anyone else who wants to dip their toes into the murky waters of #geographygalore.