I'm no expert, but I'd have thought that if you bought the easement you would have a RIGHT to cross their land. If you don't pay, then you'd just walk on it like everyone else who uses it. Simple trespass is no crime. If the council wanted to stop you, I think they would need to go to court to get some sort of order restraining you. Then you could be prosecuted if you broke that order. Since there is cost but probably no benefit to them, they would have to be a bit officious to do that.