The Met Office have issued a yellow weather warning – which could mean 40 days of rain if an old superstition is to be believed. And that could put a real dampener on yet more British summertime plans, including those made for the school holidays. Today (July 15) is St Swithun’s Day, and legend has it that if it rains on his feast day then it will continue for the next 40 days. Whether you want to believe that or dismiss it as an old wives’ tale is up to you, but the Met Office are very serious about today’s warning. Heavy rainfall is expected from 3pm until 9am tomorrow across the East Midlan…