I paid last week just before I went on holiday. I was told the closing date was open this year so you probably will be able to pay on the day. but I would phone the museum just to check. see you there??
It was a good day last year I really enjoyed it. ;D I know Mike paid at the gate last year so I can't see a problem, they're not going to turn down a few quid. So if anyone is thinking about going I think it would be ok, although as Symon says it probably wouldn't hurt to give them a phone.