First impression is it’s definitely a snug and not a lounge! Looks tight for two people to sit comfortably let alone having guests round. There won’t be much distance between you and the tv or the fireplace so it’s all a bit cramped. And to you have to go through this room, along the back of the sofa to get up to the bedrooms? Can you please post plans of the whole house, to see if there’s any room for improvement.

Its a listed building so there are limitations on building work. that said it recently had a modern kitchen extension

Just remind yourself that many families have lived in this house over the 200+ years and they managed totally fine - not with as much stuff as we live with today, I know, but still it's a lovely cottage and looks super snug already. I think I would put sofa in front of window, with TV on that wall that backs onto kitchen. Then have another chair floating in the middle, facing fireplace to create a conversation circle. Maybe another chair (with low back) in front of the TV so that you could see TV over it but ignore TV when you have guests in.

And look at furniture that is in proportion to the cottage - you're not going to squeeze a huge corner sectional in there, but plenty of room for a two-seater sofa and a chair (maybe two chairs) - just keep in check things like the width of the arms of sofa/chairs as they take up room but don't provide seating space.

I don't know what is your preferred style of interiors? You could make it work but only if you were very disciplined about how you furnished it and what you bring/purchase. I would try to make do with a small sofa or a compact L-shape and the tv, which should be wall mounted to save space. Two small side tables would be useful but plan it all out first and bear in mind the walkways that you need. Use CAD or if not then make scale paper cutouts of your intended furniture and move it around the space. I would keep the room dimensions handy when furniture shopping too. A couple of wall mounted shelves would save floor space rather than freestanding. Think about purpose and ease of use.

To make the room feel more square i would place a 2m sofa under the window and move the tv to the right of the fireplace and a love seat next to the stairwall, bookcases or slim console where the current tv is.

I would also look to widening the opening to the kitchen so you have a view of the garden and morning light and more sociable when entertaining

I suppose it comes down to how much you love the house and how much you’re willing to compromise. How many people will be living there? I can now see from the plans that the front door opens on to the living room, so if you were to place a sofa on the window wall it’ll block the radiator and a cupboard. One option could be to buy compact modular seating which you can configure as you wish.

Thanks everyone for the helpful suggestions. they are all good food for thought. @katlucy i tried to mock up yours and quite like it. did i do this right?