I like Sonia’s idea for an obelisk and a climber. The winter flowering jasmine might be nice and give you some winter colour ( p.s. I’m no good at remembering the Latin names:)). Alternatively I thought some flowering spikes might look interesting with the natural looking mix, so something like perennial foxgloves, verbascum, acanthus (think there’s an evergreen variety of this), penstemon etc. For spring flowering you also look at Aquilegia, some of the vulgaris varieties can grow quite tall (up to 1m). They do have a tendency to self seed everywhere tho but easily controlled and very pretty when in flower. I think an evergreen of some sort would look good and anchor the rest of the planting, something that’s easily controlled such as osmanthus holly olive, yew, or the upright euonymus, all slow growing and won’t be fussed about being clipped.

Thank you, this would have been perfect had the fire pit tables width been around 90cm. We are ok with the table block access to the left hand door of the french doors as in the future we will be having sliders or bi-folds. Thinking about it more, we could have it on the right hand side of the patio instead although it will some what restrict access to the single door into the garden...

You could split up the sitting room into two rooms (would probably mean boarding up the fireplace). Some sort of windows in the partition wall would allow some natural light in to the space in the middle (see this ideabook for inspiration). https://www.houzz.co.uk/magazine/houzz-tour-a-gorgeous-parquet-floor-is-reinstated-in-a-city-flat-stsetivw-vs~148736933 The only issue would be access - one of the children would have to go through the other's room... maybe a screen of some sorts would help with that. Or you (the parents) could have the middle bedroom - the French have done quite a good job with all those mirrors. The bedroom by the kitchen could then become a snug/TV room, and you'd only have to accommodate a dining table in the existing kitchen.

Hope people don't mind giving one more opinion. For the TV, the options I have is to remove it from the wall and put it in the left-hand corner of the room. I'd put it diagonally so it can be some from most parts of the room (otherwise the chimney breast is in the way). I'd keep the electric fireplace in that case. Alternatively, I can keep the TV on the chimney breast but I'd need to remove the electric fireplace (as mentioned above). I'd put a shelf or two in the hole left by the fireplace and plaster the edges. I'd probably put some gadgets for the TV (like playstation or soundbar) in their. However if I end up still not liking the TV on the chimney breast I would put it in the left hand corner as planned. The chimney breast would look a bit bear but thought I could fill the hole with wood (saw some examples of this online) and maybe put a mirror above it. Here is another picture of the current chimney breast. For the first plan the TV would go on the left under the shelves (when the sofa is removed).