As a tile importer and retailer, it's very rare for a porcelain tile to crack if installed properly. I'd not recommend juggling your Le Creuset to test the theory though... More and more tilers are using a decoupling matting such as Durabase to take as much movement out of the tile as possible. We also supply flexible adhesive and grout, so with a properly flat floor, it's rare for us to get a call from a grumpy client. We supply a lot of large format "infinity" look tiles, where you have an identically sized anti-slip External version of the Interior tile. Most are 8-9mm, so need a concrete base that mirrors the internal floor. If there is a 20mm version, then a sand & cement base can be used. As for kitchens, always tile the entire floor before the kitchen goes in. This means that the kitchen installer has a blank canvas to work on. It also means that the floor is completely sealed, so the chances of liquid ingress under the tiles (under the units) is pretty much nil. Finally, it also means that if you have any white goods that fail under the work surface, they can just be slid out, rather than having to remove what could be long an heavy lump of marble or granite to get them out. The additional cost will be negligible compared to an insurance claim...

Is does seem that the lesser known brands of LVT are the same thickness and same warranty as the major brands- the difference seems to be the colour choice and size of marketing budget. So as long as you like the colour choice with another brand then I think the cost saving is worth having. Separately the issue with herringbone over an expansive area is making the pattern meet up- generally a competent fitter will have no problems- I wonder if the issue is that you aren’t actually looking at LVT but instead floating floors (click together floors as opposed to stick down to the screed). Floating floors need to expand and over a large sized area can need an expansion strip adding which looks fine if you can add it to a doorway but looks odd in the middle of a large room.

Just on the chimney point. We knocked through between our kitchen and small sitting room. We needed a structural engineer to specify the steel. as part of the work they took out a similar chimney and supported the chimney higher up with a diagonal steel. the whole job was £15k and the diagonal steel wasnt itemised but we had the wall taken out, new plaster throughout, lights, new floor, radiators etc included. so i guess a couple of thousand pounds for the chimney removal to first floor.

Agree with Jonathan. Peninsula's always split the space in half. I think his layout is a much better use of space I think an L shaped sofa, unless the chaise/ottoman end is compact is quite a large piece for the available space. A two seater sofa and a chair would be more flexible. You could also simulate the L with two sofas with a side table between them. Think about how you live, what suits your lifestyle? If you had a rectangular table it could double up for kitchen prep running parallel to the hob.