You can walk from the park to The Victory pub, which is that perfect English pub with a dodgy dartboard and a fire that smells like my grandad’s shed. The locals are friendly, but they will absolutely give you a look if you order a cocktail. Stick to the ale. It’s cheaper and won’t make the regulars snort into their pints.
One surprising fact: Mersea Island had a Roman fort on it. So while you’re sipping your pint, you’re basically standing on two thousand years of history. The Romans probably complained about the same seagulls, too.