I never thought about mirrors as plinths, sounds cool. However I'll stick to what Ive got... no plinths, lit with LED's, and run a feather duster under it once a month... my particular kitchen gives me peace of mind knowing there is good air flow and I spot leaks immediately. Mirror acrylic is available in big sheets, and can be cut with a jigsaw, and I suppose the clips to attach them to the legs can be glued on. If you do go this route, I warn you must get the correct glue for the mirror acryllic backing, having personal experience of using the wrong stuff, it looked fine for months, then reacted badly with the mirror backing and destroyed my project... I even wrote to the glue company about it (think was Unibond), but they sent me a tube of the right stuff free of charge so can go see what it is if you need. Would love to see photos if you get these done.

I have white low sheen finish handless kitchen doors. I love them but here is the negatives I've found. The drawers had to be shallower as it had to accommodate the narrow panel that sits behind the top of the drawer front. They can be hard to open at times. I have 800mm wide soft close drawer runners and they can get heavy and it can be a work out on your fingertips. I don't have long as but I've been told they can knock your nails around a lot. And also the door handle area can also get knocked around a bit. I have 2 pack finish, so it's really tough but I've still seen a few tiny chips in 9 months use. It restricted the type of integrated dishwasher and fridge I wanted. I ended up with a semi integrated DW and handles on the fridge. The DW has a fin across the top to match the other cupboards Ive found them easy to keep clean though.

Hi Tile without UFH is very cold. You mention not wanting vinyl, but I'm assuming you mean vinyl on a roll (a bit like lino) and so I'd propose Luxury Vinyl Tiles. It is highly durable, often compared to the flooring laid at supermarkets which has high amounts of traffic. It is warmer to the touch than other alternatives such as laminate or tiles and resistant to water. They often come in stone effect or wood effect- and come as tongue and groove planks. You could also consider engineered wood but it needs alot of care.

To me it sounds like you will move as you don’t love the house (this was us a year ago- our home ticked every box but I just didn’t love it. We ended up moving). If you are considering moving then personally I would leave the layout as it is and save your money for your next house. If you are planning on making it your long term home then I’d do a side extension to really maximise its potential. Maybe talk to an estate agent about what would add value to help you development decide?