It's always puzzled me why the Thames below Staines (London Stone) is considered tidal, it is free fishing, and yet the close season is applied. I do believe with regards to below Richmond certainly, it is definitely tidal and therefore available to all anglers throughout the year, but I may even then be wrong.
Why also are parts of one canal available to fish where a river runs through and yet other canals, which are the same, you can't because of the close season? Fishing is allowed on the Kennet & Avon canal and on the GU where the Colne flows through, but on the Wey Navigation (there's a clue in the title) it's classed as a river throughout and subject, therefore, to the close season. Puzzling!