Ours is 9m x 3.77m (narrowing to 3.47m).
Originally it was two spaces -
-
4.26m x 3.47m and
-
4.87m x 3.77m
but, because the previous owners had extended which left a 'middle' room with no external window (it had an internal one 🙄), we decided to open up the space and put a wall of floor to ceiling windows at the other end to bring in more light.
We have our dining table at the narrower (3.47m) end (although we have a large kitchen diner we chose to have island and sofa rather than a dining table in there) and don't find it remotely a squeeze. That's despite having a working fireplace, bookcase with adjacent chair and a pair of cabinets in addition to the circular table/chairs.
At the wider (3.77m) end we have a three/four seater sofa along the long wall, a large loveseat at right angles to this with the TV on a sideboard on the right in a similar set up to @HappyGG above. Oh...and a coffee table, drinks trolley and two lamp tables.
We have huge rugs at both ends and loads of lamps (six - a mix of floor and table lamps) spread about the room. Walls are a fairly dark Olive (by F&B).
Imho the room feels cosy/intimate at the dining end and spacious/bright at the sitting end.