Concerns about tree roots could be from the neighbours or due to a TPO. We’ve been through this recently and have designed our extension to avoid the entire tree protection area (based on an arboricultural report-a requirement for us even to apply for planning). Despite that we have planning conditions on storage of building supplies (not near any trees), not being able to change ground levels (eg around patio areas) and being required to dig manually, not use diggers for fear of damage to roots. An arboricultural consultant should be able to advise on where and how you can build in relation to the tree, and then you would need the Council to accept the consultant's opinion. I assume the vendors must have had an opinion to plot the protection area? Also my understanding is that TPO legislation overrides permitted development legislation. As we've several TPOs, we’ve got to know the local council tree officers, but it’s the best approach as there can be heavy fines if you get it wrong.

If the TV is opposite a door with glass then I guess at some point during the day you will get a reflection or glare. It’s best avoided if you have an alternative option but what are you having on the sliding doors in the way of curtains/blinds?

Oval dining tables are able to seat everyone comfortably and a good choice. Not so easy to come by however! Maybe a glass top table would add a bit of sparkle/bounce light around the area? If you have kids an oval or round extending to oval best. My dining table is oval with extra leaf added to round top and I keep it as extended. Might be easier to find round to oval than just looking for fixed oval top? Choose a sofa with neutral but washable loose covers (ie machine wash) and add colourful cushions to make a statement. As your wood in new kitchen is dark and warm tones, follow the warm tones with dining table/chair/sofa legs in dark wood.

The garden is south facing so the sun comes through the kitchen and living room windows. We have thought about going into the the Living room, our Hesitation is it’s a good sized room with a nice fireplace. We have also thought about maybe extending out a metre or so from the kitchen to square it off but assuming this would be pretty expensive to do