Re: Car park
I found a similar story at a partly related attraction, The Telegraph Museum at the former C&W site in Porthcurno, Cornwall.
This was back in 2012 when, at a loose end in the area, we decided to see what was happening and perhaps get some food in their cafe as the weather was somewhat gloomy. The car park was a fiver before you'd even got to the building with no rebate on entry so, assuming an entry cost of around £10 each, I got back in the car and we went somewhere else.
The current story is £6.50 for parking (!!!) and you get a £2.50 refund if you spend at least £5 on entry fees but that's still ouch. I can understand them wanting to stop people parking for free then going elsewhere, and also wanting to encourage people not to drive but it all seems a bit punitive especially as the distant west of Cornwall isn't the best served area bus wise.