Help...what to do with 4 kids age 4-7 on Tuesday?

[KM]

My grand plans of spending the day outside in the park/adventure playground look like they won't happen with rain forecast....what can I do that's relatively cheap/free? I've got 4 kids (2 boys, 2 girls) to entertain, and I would rather they weren't trashing my house all day. Any thoughts most appreciated.

[Fuschia]

Has cuming museum got anything on?

Horniman does

Soft Play Bellingham?