Walthamstow Wetlands are London's largest urban wetland nature reserve, home to many wildlife species. Only 15min from central London. The cafe is open daily for breakfast, lunch and afternoon tea. 

Donlon Books is an atmospheric little bookstore on Broadway Market (in East London.) They sell rare art books, style publications, and homemade photography zines.

Great selection of books and magazine with a big focus on rare. out-of-print books Japanese photography. Can sends hours in this little shop. I'd try to avoid on Market day (Saturday) if you want to have a good look as it can get a bit busy for such a small space.

London is blessed with many fine parks, but Brockwell is a real jewel in south London. A short walk or bus ride from Brixton, or right by Herne Hill overground station, the park includes large grassy areas, the fantastic Brockwell Lido (a vast open-air pool – hectic mid-summer unless you get in early - a 7am swim is utterly blissful), tennis courts, a bowling green, a BMX track, a mini-railway, a secret garden, and a few newly landscaped ponds. Perfect for a lazy summer day.

I rediscovered this place recently having not been for years and now I keep returning. The geological galleries are my favourites.