If you have granite work top or you having an upstand around the counter so you will not need tiles around the splash back. Keep the floor tiles neutral as these are a big expense and not easily changed. You can then add colour with paint & possibly a feature wall, these are much less expensive to change & you can easily create a wow factor. Good luck

So much potential. I'm not sure if that question was for me, but I would demolish the lean to, at least partially. It might be possible to save the supports to create an open structure-hard to see from the photos. I would enlarge the French windows from the drawing room. "Too much work" is subjective. Different people have different tolerance to disruption but, as you say, the layout isn't really functional for you at the moment. It's certainly less work and expense than extending. The problem of supporting walls crops up all the time. When you're looking at a project of this size, the cost of getting a structural engineer in to do the calculations and then have the necessary steel put in place is pretty marginal. The Building Control officer will then come and sign it off, as you probably know.

A much more functional layout can be achieved in the existing room by flipping the existing hob and fridge freezer. It looks like you are currently losing a good 30cm or so of potential counter and cabinetry space next to the doorway, and it would give you a longer counter run between sink and hob. I would also add a long bank of shallow low cabinetry alongside the wall between the 2 doorways, which would give you quite a lot of additional storage space without interfering with the walkway or sight lines. Plus the narrow ledge there could help keep clutter off your work surfaces. In terms of dining space, you could lose your unloved peninsula and then add a small table and chairs. You would have to squeeze in the 60cm oven into the main work area, but 30cm would be gained by the fridge move, and another 20cm could be gained by swapping to a 60cm sink cabinet. (I assume it’s 80cm right now.).

Ideas: On the second pic towards the kitchen I'd consider removing the breakfast bar completely and a table against the right hand wall. Bench on the wall side. somehow redefine the kitchen vs. front room so the front room space runs right up to the door - some colour in the alcove perhaps? Hang the door on the other side so it still opens into the room but covers up the kitchen when sitting in the lounge so you FEEL like your in the lounge and not the kitchen? What is the glass wardrobe/cabinet on the side of the kitchen - can that go - to open up space and a sideboard instead? or at least low level only. To my eye (and I dont like too much open plan) its like the open plan has got you already and the kitchen is invading the living space!