Can't remember where I got this info, or if it is still correct. But of a council bans dogs off a certain part of a beach or a complete beach it has to provide a area of equal size with access for dogs.
So no council can ban dogs off all beaches. I have just the two dogs now, so if I'm off somewhere we plan to stay a while I will check out the local councils website about dogs on the beaches.
Some places are well know for dog free beaches such as pembrokeshire, but in most cases you can find an area of the beach where dogs are welcome.
Most dog free areas are only in place May to September.