Like many people, you might be unsure of the law, but it's true - unless they are in specially designated areas all dogs must be kept on leashes when being taken for walks in public areas.
While we watched people playing on the beach and freezing in the sea I noticed several dogs running unleashed on the beach. On the one hand I feel sorry for the dogs who really need to run free, but on the other hand I realise that some dogs are simply not social and friendly, and unfortunately it can't be left up to their owners to decide.