Hey Luke, So many options! One really helpful tool to narrowing down to what your naturally drawn to is checking out pinterest, and just google in generally. Search for Navy blue kitchens with white worktop (try different variations of your search), and take a look how others have paired their tiling and splashbacks. My natural personal tase is quite a classic/ contemprary style, and we've recently designed a lovely side return extension with a navy kitchen that looks just like this, with a white quartz worktop. There was wooden floor throughout the rest of the house, so we contrasted the open plan space with a 30 x 60 floor tile, styled in a herringbone pattern. We then carried a lip of the quartz worktop around the whole kitchen, and added the quarts as a splashback too. The rest if just then painted in line with the rest of the space. It's simple, but effective, and has allowed us to lift the space with additional contemprary accessories like a wall hung pole with hooks for decor as well as function. As I say - Pinterest is the one, and i'd rinse it for all it's worth to narrow down to what is calling to you. Hopefully thanks helpful :) Bryony Lane Valley Designs

Fishscale tiles are very Moroccan, especially in a turquoise shade. Mexican in much more colourful and patterned. Have you looked on Pinterest? Great place for ideas, as it Instagram. Here’s some ideas

As mentioned by the others, having tiles and upstands together would look rather bizarre. I’d suggest removing the upstands and adding white or dark grey tiles. You could also add white tiles with dark grey designs to maintain the colour scheme that you’ve got going. Tiles would also be much easier to clean, and if you choose dark grey tiles, any stains wouldn’t be visible at all. I recently got my entire kitchen redesigned with the help of these kitchen fitters called Saturn Interiors. They took care of all the minor and major details, so I didn’t have to worry about any of it. If you want to, you could consult with them about this issue. I think they could provide you with better solutions too.

If you want to modernise the kitchen then yes, knock them off, reskim the walls and have no tiles but that’s where you start to think where does the spending end because it looks nice with upstands which then means swapping the worktops so they’re both the same colour. Those fascias are from an old design range. You could keep the existing carcases as long as you like the design of the original kitchen so just having new doors is the cheapest way.