This will be a challenge !

This jigsaw is a personalised one of a copy of the Ordnance Survey map of an area around the owner's home. There is no indication on the box as to the area depicted, and no picture. Fortunately I know the owner and the area so do have some idea of what it will look like but most of  the pieces look alike - white background with lines representing roads, rivers, footpaths and drainage dykes with some villages and two towns. I will post the pic when it's done - but it will take some time!!