The benchtop will be dark grey (the ones you see are temporary), black handles and the tiles will be white with light grey grout. The paint on the walls will stay as is (light grey). Thanks for your thoughts guys. Would anyone go all the way to the ceiling? why/why not? Does the herringbone pattern influence your decision?

Hi ucheokeke1 colour matching to the tile should be relatively simple as already explained. However even if you find the right paint colour, unless you ask for optically clear glass (known as Starphire glass in Australia) your colour will be skewed by the natural green skew of ordinary glass. If you can source a coloured glass splashback that's close to your chosen colour from a standard range you will be OK with normal glass. If there is nothing similar in a standard range, the only way to ensure true colour representation is to pay the extra for optically clear glass. I hope this makes sense.

Try a slim porcelain sheet in a concrete look finish. The large format size means you'll probably need only one, so there'll be no grout lines. Have a look here, at the Portland 3.0. I think the Kerlite range also does a concrete look and is larger, at 3m long. The other advantage of a porcelain tile over actual concrete, is that you just wipe it down. Concrete is porous and will stain.

Your kitchen is small and already quite busy. I would make it as simple and clean as possible. You can't beat ceramic tiles for cost, durability and ease of installation. Have a look at Johnson's Spectrum range to see if you can match the green. https://www.johnsontiles.com.au/product/spectrum/?utm_campaign=1602072422&utm_source=google&utm_medium=cpc&utm_content=304640004469&utm_term=&adgroupid=61761480198&gclid=CjwKCAjw_YPnBRBREiwAIP6TJ0idAicM8vfEevC-WrwRVNmbtUPHfDAjvNpkaOIo0hzN0dwMw9u1rxoC0VkQAvD_BwE You will get a neater finish with ceramic tiles than you will with trying to work with DIY stainless steel, particularly around the edges. There are lots of online resources to show how easy it is to lay smaller ceramic tiles. Leave the large format porcelain tiles to the professionals. Best of luck, Dr Retro of Dr Retro House Calls