Where to hold a surprise 40th?

[Toklas]

I am planning a surprise 40th birthday party for my better half. I was planning a picnic in Ruskin Park, but it looks like it's going to pour with rain. Can anyone recommend a place we can go as a last minute back up? There will be about 20 of us, plus a lot of toddlers, and my partner is coeliac (no gluten) and vegetarian.

Are there any child friendly, coeliac/vegetarian friendly pubs or cafes with enough room to accommodate us on a Sunday????

[Peckhamrye]

We had our wedding reception at The Lordship pub in their upstairs room, it was lovely, really well looked after, can't recommend enough.