The entrance to the park is unmanned (but monitored by CCTV). You put your payment in the envelope, detach the stub and place on your dashboard and you’re free to roam. The park isn’t fully open yet so the café and toilets at the North entrance are currently closed but the visitor centre nearer the East entrance is open and has a great thorough permanent exhibition that has answers to many — or any — of the questions you may have in your head. I for one wanted to know how long it takes water to flow from the source to the mouth, 2500 miles downstream. The answer: 90 days.