Probably no harder way to actually successfully find a meteorite by simple random searching. You stand a much better chance by looking within known strewn fields for pieces not found originally. Thus, for instance, people still find meteorites in the Holbrook, Az strewn field, many decades after the fall. I realize you are in England, but the way you're going about things will give you about a snowball's chance in Hades of actually finding a meteorite. Good luck of course, but it may take you several hundred years using such a technique....