Yes, thirty years ago it was free! I still like to go there now and then, despite the queues for the few car park ticket machines and the people who never have the right change (that usually includes me!)
When I was there a couple of years ago I met one or two people I sailed with back in the 80s, we had a chat and I reminded them that I used to bring my little duaghters with me - then shocked them by introducing the lovely tall slim blonde I was with - one of the little girls thirty years on! I think that really brought home the passing of time to all of us.