I'm also now imagining someone actually using this guide, walking into the sort of city centre gastropub popular with tourists, striding confidently past all the serving tables up to the bar, identifying a group of very drunk lads from out of town as "regulars" and trying to join in their banter, and then attempting to offer an even more confused Polish barman a drink...

Indeed. But beyond that, I first visited the UK in the late 1990s and found that a lot of the pub culture I had learned from 20th-century literature, film, or even supposedly contemporary episodes of Eastenders was already out of date. The merger of pubs into large chains, and the importance of serving food to ensure profitability, also came as big surprises. And by the first decade of the new millennium, it really did seem like every service staff I interacted with on brief forays to the UK was Polish, Lithuanian, or Latvian.