We vote tiles! If it was my kitchen (and mostly because I'm a messy cook) I would be inclined to tile (or glass backsplash) anywhere that might need to be wiped down-e.g. behind cooker, along any counters where I might be doing any food prep. This gives you plenty of options-you could tile behind cooker and counters in metro/subway tiles, but be careful as it could look busy with the granite and wood grain of kitchen-it will depend on the grout. Alternatively, you could use big clean glossy tiles like this marble look above.

Colourhappy sinking the fridge in the wall is my plan, just not right away. I don't even have to steal space, it'll fit into the 'triangle' but I would need to take the kitchen door away and move the utility door. I'll make do by adding an end panel to the right of it to blend it away when seen from in the dining room. Right now it has to stay where it is. As for tiles, I'm somewhat stuck because the worktop has a marbled vein though it. It's white but not brilliant white and next to white wall tiles, it'll look vanilla. The veining through it is grey with a tiny touch of copper/burnt orange through it. Hence why it's called Calacatta gold. I live metro tiles but it's to right here. There is herringbone on the floor so though I do live patterned tiles, again it needs to be simple. Right now I'm considering a glass slab. Any thoughts on that?

My personal view is that tiles in a kitchen are a harbour for dirt and a pain to keep clean. Smooth, sleek surfaces are best. We went for granite upstands to match the worktop and a contrasting but neutral glass splashback.

There are a huge array of tiles you could choose. Even metro tiles can look good if you choose a nice finish like Zelig, first pic below. Go onto Pinterest or Houzz photos to give you more ideas. I would take them up to that wall unit you have and behind the cooker go up to the hood.