Family 2 Day ticket valid on Wednesday 22 & Thursday 23 August for £40 (this includes car parking for both days).
"A Family Ticket is valid for 2 persons 12 years and under and 2 persons 12 years and over (one of whom must be 18 years and older), or 3 persons 12 years and under accompanied by 1 person 18 years or older."
This was a web deal and I have the tickets printed to simply scan at the barrier to enter.