Do you have any pictures? What do you consider your style? If you don't have pics what pictures capture what you are after? I was deciding myself between tile and glass and now considering mirror to bring in extra light. I've seen mirror a lot lately used as splashback even smoked or black mirror, so really depends on how you see warm modern as a style

No to the grey - your wall seems to have a green tinge in them, so I would say either green/grey or a warm white tile with darker grout. If you choose the right grey/green, it is a classic look so shouldn't date. If you are a bit scared to choose colours, why don't you get a couple of warm white sample tiles and put where the splash back will go. You will soon see if it looks too stark....(maybe another idea, but possibly not a good one - why don't you see if you can put a few pages from a blank sketchbook in the whole area where the splash back will go (not super white white, but a warm white). That could also possibly highlight how stark (or not), the white may look. I can see what design tank is saying, as your cupboards appear to be more cream than white in the photos and if this is the case, then I agree the white will most likely look too stark. My cupboards in kitchen were white (but a warm white not a cool white). The stone bench tops also have the little speckles of stone in them..I can't remember the colour Ocean foam/Osprey.......but even with those colours and them not being cool whites, I thought the white tiles looked too stark against them. I therefore went for a glass splash back and ever since I then went to think of designs for my bathroom renovation, I constantly regret going with the glass in the kitchen and modernising the house too much..........definitely don't do glass if you are wanting to keep a classic charm to the house. In a long winded way, I think yes, I also think you should just stick with the grey/green. It will make a statement. Not the right shade...but another example....it may be hard getting the colour of the tile exactly right given that the walls are already painted and the tiles need to match.

Hi Caroline, A few inspiration photos for you, try using subway tiles in a stacked style for a modern contemporary look, much more stylish than the overdone normal subway look, would look great in both areas, your tile store will advise the size of tile that will best suit your requirements.

We had a glass splashback for over 10 years. I loved how easy to clean it was and it had a simple minimalist feel. The previous house had tiles- you will always have the issue of cleaning the grout and at some point I always had a stain I couldn’t get out - not sure if they have different grout now but I think at some point there will be a tomato sauce or saffron splash that you can’t get rid of.