Had a trip to Mountfitchet Castle in Essex with the kids earlier this year and had a great time also walking around the Toy Museum there - http://www.stanstedtoymuseum.com/
Here's a few pics:
And if you are wondering where all the Action Force is, here's all I could see!!
I asked them if they would consider re-naming the Toy Museum 'Gunghoeddie's spare bedroom' but they declined as the public may think they were going to see something bigger!!