I was there with BMWCC EA region group - it was indeed wet early on then cleared up a bit leaving the day overcast & a bit drizzly. However, I thoroughly enjoyed the day, it was the first time i've attended this event although I've been to the museum many years ago, so it was good to visit it again. I have read comments made by visitors on another forum & also on FB and some have been negative saying it's the same old format year after year and that attendance this year was apparently less than previous years - I can't comment on that as this was my first time - but what I will say is that a lot of people have put a lot of time & effort into this event to make it a successful as possible and in my opinion they did a great job.
OK some of the 'independent' car clubs didn't get the numbers they usually get, that could be down to a few reasons, not widely promoted with their club/group, or have been before, don't like the parking arrangements (on the hill), or simply the rotten weather put them off.
I don't care what anyone else says - I had a great day!