By the way if the weather is bad then some of the museums can be really good for sarging. The British museum in Bloomsbury is really good for sarging as there are usually a lot of suitable sets to open. And there are also shopping malls at Shepherds Bush and Stratford. They can get quite busy by the late afternoon. The bad weather can also be an advantage for street sarging as it is easier to encourage women to go with you somewhere warm and dry for an instant date like a nearby coffee shop. For night game check out the Roadhouse club in Covent Garden and it is well known as perhaps the easiest place to pick up in.
By the way if you are looking for new wings and want to meet some of the real masters of pick up to learn and get advice from them for free, then I highly recommend attending at least on of the weekly London Saturday Sarge;
http://saturdaysarge.urbanistgame.com/when-where/