My two friends and I only stayed in Donovan's apartment for a day since we had reservations elsewhere in the city that we moved to afterwards for a longer stay.
I can say for Donovan that he is very easy to communicate with and he is very well prepared for all the guests that he hosts in his home. The flat is located in a fantastic place (just a hot, skip and a jump from Waterloo Stn.) and you can easily get around all of London from there. In addition, everything you need is available, everything was tidy (there is someone who comes to clean regularly), and the key exchange was handled very efficiently even though Donovan wasn't at home when we arrived nor when we left.
For my next stay in London, Donovan will be the first host I look up!