After an unusually long journey to our destination, due to DLR closures, we started out at the south end of Hampstead Heath, near the Lido and cafe. (My friend Meredith lived in London for awhile and when I asked her about it she said it was frustrating to always depend on public transport. I shrugged it off, refusing to believe London had any flaws, but she's right. When the trains are shut down for one reason or another it can really put a wrinkle in your plans.) We let the kids play in a playground for a bit and then we ate lunch at the park cafe.
I've added Kenwood House to my list of places to visit without the kids...