This flat is all about location. A perfect spot in Fitzrovia to use as base camp for exploring London! The trip from the Airport is simple by either Elizabeth Line or Heathrow express to Paddington then Elizabeth Line so you need not wear out the rollers on you bag, and there are 3 or 4 Tube station a short walk (depending on your idea of short) away. But given the location, use of the tube can be reserved for rainy days or exhaustion at the end of a long day exploring or making merry at a remote pub. It only a brisk walk to Regent's park, Covent Garden, Picadilly, Soho, and an interesting, if longer walk to Camden, Southbank, the Borough Market, and so much more.
There are tons of food shops near by and a daily set pop-up street food vendors a few steps away as well as Tesco and M&S locals close to hand.
The flat itself is a good size for a London flat. There is an actual bedroom with a door (you may want to close this on Thursday through Saturday nights when the pubs are going strong) and it is quiet and isolated from the street noise from the front of the unit. The bed is firm and comfortable, although given its position, one person will need to squeeze side-footed past the end of the bed or climb over the other to get up in the morning, but this was not terribly difficult. The living room is good sized and while the TV is somewhat small by current standard, it is big enough for the occasional night in with a movie. Remember to bring an HDMI cable for your laptop if you plan to use your streaming services. We didn't try the fold out sofa for sleeping but for sitting it is not terribly comfortable, as is the case with many fold outs, but it is fine for lounging in parallels to the cross supports and there is a comfy, if somewhat worn, chair with cushions enough so two people can each find a spot.
The kitchen is ok for making eggs and rashers and porridge for breakfast and heating ready-made meals in the oven or microwave, but it is not well equipped for any elaborate meal preparation. So if you plan cook elaborate meals, you may want to bring some of your own kit.
Overall, our experience was great and the flat felt like home (the one you have immediately post-uni anyway) after the first week. We stayed for 3 weeks and found it was workable for that period, although I think probably optimal for a stay of a week or less. Your mileage may vary, of course.