Richard's place is super clean, comfy, and in a really lovely part of London. The attic room is super cool and the ceiling window opens up to a fantastic view of the city in all directions. It is a bit out of the way from the more 'central' areas of London (like Buckingham, British Museum, etc..) but it's about a 30-45 train ride in, and the tube is really efficient and easy to navigate so if you're comfortable on public transit then you're all set. Greenwich itself is lovely anyways, so be sure to pop into town.
Richard is a wonderful host, very accommodating (he allowed me to stay an extra three nights since I had an unplanned weekend), and a real pleasure to speak with. He makes sure that you have everything you need upon check-in and is always available by phone for questions.
I would certainly stay with Richard again on my next trip to London.