Again it depends on the look you're going for and it's difficult to advise without samples of the kitchen unit and floor materials. Always plan the room as a whole rather than looking at elements in isolation. That said, a good dependable choice would be a satin white brick or square tile. You already have quite a trad kitchen so I would go for something a little more contemporary and steer clear of anything with a bevel. The balance between pale grey units, darker grey countertop (plain) and fresh white tiles should work well, particularly if you can find somewhere for some open shelving in a light wood tone to balance the floor. I've attached an image of a kitchen I refurbished in an Edwardian house I subsequently let - excuse the quality of the picture, it was for my info only not for marketing but it gives you an idea of how satin white tiles can work against a stronger neutral, greys and wood tones. That was a mix of two F&B shades but something like F&B Ammonite, Cornforth White or Purbeck Stone or FE Bone White would work with flooring, tiles and units. This is just a steer. It really is essential to do sample boards and look at how the shades work together. Keep the paint shade unsaturated and steer clear of DIY paints. The branded paints are much richer recipes. If the budget will stretch to it, get some accent lighting in - lighting is often neglected but can make or break a scheme.

Glass gives a modern look. Tiles can also look good and is a more traditional look.

Subway tiles as a splash back and grey vinyl flooring for a guest house in Elands bay

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.