Me and my girlfriend stayed at Alejandro's place for 2 night. He was very welcoming and super nice! We got the whole apartment for ourselves.
The size of the apartment is very good, we had everything we needed. There is a bus stop just outside of the apartment taking you to the Brixton tube station in 5 minutes, and from there you can get to anywhere in London.
The only downside is the bed. Not the most comfortable in the world, but that shouldn't worry people too much.