Communication fantastic from the beginning. Lorraine is quick to respond and answer any questions. She sent the keys a week before we arrived. The flat is small, but everything you need is there. There are a few flights to get up to the top floor, but we managed fine with 5 large suitcases.
The kids loved the bunk beds and there were lots of toys for them to entertain themselves with. The sofa bed was also quite comfortable as was the main bed.
All appliances were modern and clean. There was an issue with the hot water - lots of fiddling had to be done to get the right temperature, and warning everyone else to not use the kitchen sink! :). This has nothing to do with the hosts but with the building it seems. Perhaps it's something being worked on and will be fixed soon.
Great location. Very close to the bus stop and to the underground stations. We generally used public transport in the morning and took an Uber at night.
As there is only one bathroom, I think 4 people or 5 max is best option as it may get uncomfortable past that.