I recently moved to the UK for an MSc and could not have picked a better place and host. David and Ana are incredibly thoughtful and have a wonderful home. The room itself felt like an oasis from the hectic London atmosphere and David was always available if I needed him, he is easy to communicate with, and lovely to just have a chat with.
The house is close to all major lines and is really accessible for anyone needing to get around London. You'll have your pick of grocery stores, shops, and pubs as well. I really cannot recommend David and Ana enough. I am in their debt for ushering me into London in such a gracious and helpful manner.