"Hi - re the Parks, specifically Battersea Park's description.
I'm sure "Getting In" to Battersea Park is better than 4/10, more like 8/10, and being almost flat it's very accessible. Public transport - not just the trains from Waterloo and Victoria (and Surrey and Middlesex) plus the London Bridge route and the 137 bus but several other buses pass the park or along Battersea Park Rd from the 452 from Kensal Green and Kensington, the 344 from Liverpool St, and there's the 156 from Wimbledon. Even the 360 bus (South Kensington to Elephant & Castle) stops just over Chelsea Bridge so the visitor gets a short walk across Chelsea Bridge with fabulous river views with the Power Station, or you can catch one of the 3 buses that cross the bridge, including the 44 (Tooting-Victoria).
As far as fun goes - it's a wonderful place to learn to rollerblade especially near the Pagoda (lessons and group skating) and what about the bike hire place which hires out all sorts of bikes for all ages?
Lastly, Battersea Park's famous annual November firework display is brilliant and excellent value."