We are a family of 5 with three boys ages 7 through 13. We spent nearly two weeks at Karin's place this summer and were extremely happy with our experience. The home was perfectly situated in Putney which was a 7 minute walk to the closest underground station for the District line. From there, it was no more than 15 - 30 minutes to most places in the city via underground. The District Line is air conditioned which served us well for the few days of high temperatures so we could still explore the city.
The house itself was clean and exactly as described. There were lots of toys for the kids which helped on the quiet days we spent at her house.
I can't thank Karin enough for her excellent suggestions and communication throughout our trip. I'd highly recommend the restaurants she suggested - in particular - Putney Pies!
Take care and thanks again.
Don