I absolutely loved this, even if I got side-tracked every five minutes or so looking up stuff relevant to the setting and area.
The remark about Southwestern accents made me at first think this was somewhere in the Southwestern US, the British usage of words though quickly made me realise that West Country was meant. "Porthwarren" is such a stereotypical Cornish place name, which made me think of Porthgwarra in Land's End, but the line about the Church on Church Street confirmed that the story takes place on Saint Mary's/Ennor in the Scilly Islands, Hugh Town/Tre Huw, to be exact.
I may have a geography obsession...
(Now I wonder what place "north of the county" in regards to the uni Billy studies at is meant. Devonshire? Somewhere else in the UK?)