The King George 5th is an SSI and there is a sailing club based there. The William Girling is also an SSI.
The Walthamstow (or Tottenham) Reservoirs are again SSIs and are popular with birdwatchers, and anglers.
If you ever walk the Lee Navigation, try and find the railway arch on the bridge over Walthamstow Marsh - it's where A V Roe first set up shop. Apparently he used to crash quite a lot into the marshes.
