Floating down to Camelot

I'm using an OS map dating from about 25 years ago, because it shows the entire island in 1:25,000 scale on a single side of the map. The newer editions in this scale are two-sided, and I can rant until I'm blue in the face about the hideous awfulness of 2-sided OS maps. As a result, my map is getting increasingly inaccurate. Loads of paths have either completely vanished, or still physically exist, but in a perilous form onto which only a fool would venture.