The boat is a great experience for people who haven't been on a house boat yet. Location is pretty cool - as described. Simon welcomed us warmly and also provided some food in the fridge.

Unfortunately, the area for guests is not as large as expected from the listing. We expected to have two rooms - one living room and one sleeping room. However, it is essentially one room sub-divided into two areas - these are connected so that you hear every sound of your neighbor. You'll have to be good friends in order to be using it together :) It is definitely not spacious enough for four people.
We were three people staying there - me, my girlfriend, her mum. We like each other but I didn't plan on sleeping right next to my girlfriend's mum, if that makes sense.
I recommend to use the boat as a couple, potentially with one small kid. You pay for the boat experience - which is worht it for 2 nights. If you are searching for cheap within central London, there are potentially other listings for a lower fare.