Did some research into water owned by our largest nature conservation charity, the National Trust. They own so much water across England, Wales and Northern Ireland that I did a bit of digging as to what was available on a day ticket, or free basis.
They publish some information on their website but it’s so out of date I had toi visit a few and make a lot of phone calls to get some semblance of order.
Also have now been approached to write a section for a book which is quite exciting, only a short run UK book but once done the publisher has mentioned trying to get interest across the salt (no not france!).