As you enter to your left there is a free group ...

As you enter to your left there is a free group meeting point where the guard briefly explains to you the main points on interest . Personally I think it is over priced. The ticket is 30 pounds or 27 if u dont want to pay for a donation ( I paid 27) i enjoyed the day but it isnt good value for the money.
Outside near the ticket office is a public bathroom for 50p.
There are coffee shops and icecream parlours around the ticket office too.