I recently stayed at Seivar's apartment for 2 months in between my corporate housing and settling into my permanent place in London. Seivar is an amazing host - I immediately felt comfortable right off the bat. He was super helpful to give tips around Clapham and London in general which made me feel at home quickly.
In terms of amenities, it has everything you need for a short or long term stay including plenty of clothes/storage space in the room, kitchen supplies (including a nespresso machine!), and a comfortable living area with Sky, Netflix, etc.
On a personal level, he was the perfect host/roommate - incredibly clean, conversational and fun to chat to, and also respectful of personal space/alone time. Couldn't ask for much more!!
You will definitely enjoy the space and all Clapham has to offer!