We stayed at Mashas and Johns flat four three nights and enjoyed every second of it. The apartement is located in Lewisham (10-15 min by train from the city centre which means you're in the very heart of London in no time) in a very lovely and calm neighbourhood.
Sadly, we didn't meet our hosts in person as they were gone over the weekend we stayed but still they kept contact with us all the time and assisted us whenever we needed any help or advice.
The flat itself is small but very cozy, perfectly clean and tidy which makes you feel comfortable from the very first second.
We slept on a sofa bed which was perfectly fine for us. Yes, it made quite a few creaky noises but that didn't bother us at all, someone who's a light sleeper should bring earplugs though.
In short: We've got nothing to complain about and would happily stay at John and Mashas place again!
5/5 stars *****
P.s.: Be prepared for the softest towels that ever touched your bare skin!