I grew up in Brighton which is full of cheesy bars like this. If you can handle being surrounded by multiple screens playing Kylie at full volume, its pretty much the cheapest bar in central london. The cliental is so varied its great for people watching and completely un pretentious.

A beautiful old school bookshop, floor to ceiling photo books. Heaven.

Fortitude Bakehouse, a craft bakery, hidden away on a quiet mews in Bloomsbury. 

Melrose and Morgan is a grocery shop and kitchen providing freshly prepared food and artisan products in the heart of Primrose Hill and Hampstead Village.

The walk along the South Bank from Westminster to Tower Bridge will take you past a plethora or interesting sights and cultural hotspots. There's always something interesting going on too.