When we were in London, we ate fish n chips several times at different pubs. You're right, it's a great base to go pub crawling on! Also, it was much better than what you'll get at Long John Silver's or Capt. D's, but they might do in a pinch. Like Beachnut said, there are lots of seafood places on the beach; check them out! Schooners or Spinnakers are right on the beach & their menus are on their website.