We're very familiar with London and the Clapham/Battersea area having lived there for many years.
The Good: quiet street, two bathrooms, outdoor space (the jasmine scent was heavenly!), good quality linens and comfortable beds, although they are not King and Super King by North American sizing. One is a Queen sized (60"), the other just a regular King (72"). The flat had been cleaned well and Joivy did a good job of communicating with us.
In the interest of providing a completely honest review: the furnishings are grubby. The couch is stained and sagging, there's a massive stain on the headboard in the main bedroom, and an overall musty smell if the windows hadn't been open. The extractor fan in the main bathroom just blows the steam around. The internet was terrible, even sitting next to the router and doing the usual unplug/plug in, we often had speeds of less than 4Mbps, not the advertised 8 MBPS, or no signal at all. A fuse blew shortly after our check in as two people tried to plug things in at the same time - fortunately there was a QR code to scan to get more info on some of the quirks of the flat. We stayed for 6 nights so were actually trying to cook for ourselves. The kitchen amenities were kind of random, a functioning corkscrew would be a useful, as well as oven mitts/pot holders to get stuff out of the oven.