We’re lucky to live in an area of London that has lots of local parks within walking distance. I think it’s a common misconception that cities are noisy and industrial and not at all green and pleasant (quote from a friend who was visiting “wow! It’s so much LEAFIER than I was expecting, I thought it would be all sirens, huge concrete buildings and graffiti”.)
As well as all the big central parks – Regent’s, Hyde, St James’s, Green and so on – there’s lots more local ones spread out in the outer regions of the city. And they’re such a brilliant space for children; we actually use them more than our shared garden.