You could mount a TV which can swing out from the entry wall from the main house, or on the one opposite one near the back sliding doors, or on the floor, in the corner. Depending if you need storage on the back wall, you could have your lounge at the back of the room, or have a walkway between the back wall and the lounge. An easy moving lounge is great for moving into different positions around the room. I like the idea of the bar as a drinks trolley. Actually furniture on wheels is great for rearranging whenever you like. I usually have wheels mounted to furniture as I live on my own and it just makes it so much easier. Another idea, is a buffet across the wall of the three windows and a tele positioned placed above or on where the brick wall is in the middle of the three windows, and the buffet can act as a bar and whatever else.

Bump.

WOW!! What an amazing change! Especially the rear exterior. Your team really brought it in the future! Well done.

Ok. Very first thing is to address your damp problem. Mould is insidious and very bad for your health. Get that right before you spend money on anything else. There is also no point in having floor area you won’t use.