At our last trip to London we made a stop in Brighton..
That was definetly the best idea because Brighton is a wonderful alternative City at the ocean with many little cute streets (The Laines).
In North Laine you can find a lot of Vintage Shops with amazing stuff and sometimes a flea market.
Don´t miss Cloud 9 Cupcake. They have the best Cupcakes.
The best idea to enjoy the beach at the evening is a carousel ride. Don´t be afraid to feel like a child again.
Enjoy this magical city. You will have a great time there.