You’ve already seen a picture of the Essex-Suffolk border. Assuming you’ve seen Constable’s ‘The Haywain’, that is: the Stour (the river into which the farmer has cleverly driven his cart) forms the county boundary, meaning the land on the left is Suffolk, that on the right, Essex. Years of David Beckham and jokes about girls in white stilettos had rather inclined me against Essex, so when I moved to Suffolk it was galling to discover I had a Colchester postcode.