I highly recommend Lauristons, Putney Branch. I let with them in June and they were wonderful. I dealt with Allayen Tan, he was completely professional and went out of his way to assist in securing me a property. I have used a number of agents in London and I would say they are one of the best. Allayen was completely honest with me about the property and went above and beyond. Hopefully I will be staying in the property for some time, but if I ever do need to let a property in London again, my first call would be them.