P-E-R-F-E-C-T !
Really, we missed nothing. Sarah's and Simon's small flat is really nice, wonderful for a few days in London. Not far from public transport links, we can easily get to the city center.
There is every equipment needed, the bedroom is OK, the kitchen has everything and we even had an umbrella, which was useful to survive under London's rain. All was perfectly clean at our arrival.
Sarah gave us all the information needed, everything was clear for check-in and check-out and was easy.
As expected, the main road is a bit loud during the night but we were informed.