Six frost-defying members of Swindon’s Seahorse Dive Club—Bill, Chris, Pete, yours truly, Tom, and Glen—braved the Arctic-esque charms of Somerset’s Vobster Quay last weekend. Armed with drysuits, grit, and a questionable sense of adventure, we plunged into water so cold it made penguins reconsider their life choices (6°C, give or take a shiver). Visibility? A generous 5 metres… if you…