Yep, not only are there park regulations and restricted flight zones covering most of London, but they come under the Congested Areas rules if you fly with a camera.
You really cannot fly in Central London at all. Not a great place to own a drone!
Anyone fancy testing their skills inside a hall, 57 X 36ft? It is in central London so if you live or work here you can fly, inside of course. Let me know,,,Chas.