Hard to find good outside spaces and the weather is a factor. Outdoors I mainly skate at Emirates stadium - it's big, pretty flat, no traffic, no hassle from security, there are other skaters, the surface is fairly smooth and free of debris, dries well, there are toilets. You just need to avoid match days. People have told me that Victoria Park is good, also Dulwich Park, and Stratford around the Olympic Park. If you do a lot of outdoors then your confidence goes through the roof when you get indoors, and vice-versa!