The floor and cabinets almost look like the same color. I would lighten the cabinet color - making sure it doesn't clash with the floor color. I would also modernize the open cabinet above the microwave by removing the moulding, or adding a door. I'd find an inexpensive countertop that pops against the wood (or painted) wood cabinets. Change out the cabinet glass to clear, and do a new backsplash that brings it all together. And, finally add a cool light fixture, and maybe a kitchen rug.

My downdraft is great with outside motor so not too noisy. Having said that I would also have been happy with a ceiling extractor if I had the space above for the venting.

It's definitely more centered than mine is! My house was built in 1945 when stoves were a lot bigger and that's why my range hood is bigger than my electric stove. Anyway, when you put up your floating shelves, you can either make the left size longer and the right side shorter. It will work that way unless you want symmetry. Then, I would suggest you make the shelves the same size and put them up in the same position on both sides of the range hood, just like a mirror image.

Which would look better tiles or glass and what colour? Would it be best to cover the whole wall, half wall under the range hood or just between the range hood and cooker?