Lovely flat. I don’t know the market for that area at all.
But guessing your main market is first time buyers, landlords or downsizers (e.g. relationship breakdown). Most likely household is a 20s/30s professional couple, possibly pregnant or with a young child.
They’re your Insta generation, so you’ve got to grab their attention and sell a lifestyle. They may find the decor a little old-fashioned, spartan and pale (dark walls are a big thing). Suggest it needs to look a bit more like this kind of vibe: https://www.houzz.co.uk/photos/ss-h-eclectic-living-room-phvw-vp~121074860
I think it’s easily done without much outlay or hassle, then new set of photos. You could try painting a feature wall in living room and/or main bedroom and losing some of the patterned bedspreads, curtains, rugs etc. Then dress with stuff you already have in similar colours. Put a (vibrant drum) lampshade in the bedroom.
Also, the second bedroom isn’t being shown to its potential. It looks so narrow and the bed is next to the door with no room for a bedside table. Could you reconfigure the furniture and put the bed under the window widthways (says the room is 7’6” wide so should fit) with scatter cushions and move the wardrobe behind the door. Put a rug down. That would make it look wider and more useable, as either a study with spare bed/daybed or baby/toddler room, which is what people will most likely use it for.
Maybe dress the kitchen a little more to give pops of colour: bowl of oranges or yellow vase. Same with bathroom, which looks a little sterile, by adding deep blue/grey (to match the floor) towels and a couple more plants.