Yes, these are nearly always conversions. They don’t have windows because the walls are internal...otherwise they would put them in.
A property with just one external window or set of patio doors doesn’t have enough light.
It will be cheaper because of this. People will point out that there is a place for such properties as not everyone can afford the standard 1 bed flat with the luxury of windows in the bedroom and bathroom, or a studio with windows in each room. Windows have become a luxury now!
If this is what you can afford, and you can get a mortgage on a property without external windows and the location makes it for you and you value the location more than a window which you could get. In a cheaper area, go for it, as long as you have your eyes wide open to the issues of living in it or possible issues reselling. If it’s Ann pensive area and Richmond clearly is, then there will always be entry level buyers who like you, perhaps cannot afford everything they would like and have to compromise.
If however, you can get a property in a similar area with a window, don’t choose this. New conversions are sold at a premium and this could drop in value before it recovers and if people can buy a property nearby with a window, they will. Only buy this if it is substantially cheaper than properties with windows. Otherwise when you sell, people will know it’s not a good buy if they can get a windowed property for similar price.