We (two of us) had the pleasure of staying at James' for just shy of a week while between homes. For our transitory needs, it was comfortable and enjoyable. We also knew the (lovely!) area well, which made it all even better.
While not at all a dealbreaker, I feel that I underestimated the effect that being partially underground would have. It was harder to get natural light during the day, the ceilings were very low, and sounds from the home above easily found themselves to us. On the flip side, it was easy to keep bedrooms dark and warm (the radiators did a great job!), the shower was great, the beds comfortable, TV fantastic (with AirPlay!), and kitchen very useful. We had everything we needed and more. A truly tremendous value.
I only interacted with James over messages, but he was kind in his communication and very understanding. I wouldn't hesitate to recommend a booking with him.