I had a similiar situation last year when a gentleman blocked our progress by standing in the middle of the path with an outstretched hand despite riding at walking pace, on a grass verge a couple of feet from the main path.
So we stopped to see what was up and he was quite pleasant in his approach.
Apparrantly he had just been buzzed by a cyclist traveling quite fast (we had seen the guy and he was going at quite a pace)
So we had the usual where is your bell, permit, you shouldn’t be on a footpath stuff.
Looked a bit confused when I explained it was a shared use path and part of the national cycle route network and them slightly apologetic as I pointed out the red and blue cycle route sign on a post a few feet away.
However the issue was created by the guy on the bike travelling too fast in a busy, inner town part of the route, conversley we had encountered a number of inconsiderate pedestrians, dog walker, anglers etc deliberatly blocking the canal path over the ride, also very considerate and nice folk from the same groups of users.
So as per usual, there are people with a crap attitude everywhere, ignore them where possible. ?