We could hear some of the conversation through the open window from the street as we were looking at the menu. It was definitely English. I lived in Wales for 4 years and can understand most Welsh accents (as well as speak a bit of basic Welsh).
This isn't an anti-Wales or anti-Welsh rant, I love the place. Went to uni there, been on holiday there, been to races there (and stayed in many friendly B&B's, eaten in many excellent pubs/restaurants), it was just this one pub where the atmosphere was a bit unwelcoming. Still got served though, they were happy enough to take our money. 😉