There are many great parks in London to choose from, but Hampstead Heath is by far my favourite; a lido, Parliament Hill with a great view of the city, ponds, woods and plenty of space. It’s a great place to hang out in the summer, but also presents a lovely walk in the winter. Address: (As it’s so big obviously it doesn’t really have a specific address but there are 2 main entrances) Entrances by Gospel Oak or Hampstead Heath Entrance.
A peaceful park in Kingston Upon Thames. You can see lovely houses and gardens across the river. It's a wonderful place where you can take a rest with your family or friends. I recommend you to take a walk after having lunch or dinner in riverside restaurants near to the park. It's not big, however, very enough to feel the beauty of nature. I've done some location drawings here which was quite exciting. Just seat on a bench and enjoy the comfortable atmosphere.
It's a members-only library but you might be granted access with a research request. The writer's room is great but there's a few special, hidden corners among the bookshelves to tuck yourself away in.