You may have already made a decision on this but I thought I'd just weigh in with my thoughts anyway ... six months ago we finished fitting out a new kitchen and we are thrilled with both the look and the practicality of it all. Initially I was going to go down the glass splash back track but eventually I chose tiles because I decided that, for me, the seamless splash back was a bit bland and same same. I also love blue, brown and white as a palette – and the tiles I chose were just slightly wonky (not too crazy – they still had to be easy to wipe over etc), rectangular, hand-made Spanish tiles in a lovely duck-egg blue. The slight wonkiness means they catch the light beautifully as you move around the room. The benches and cupboards are a warm white and the large island bench is a fantastic slab of spotted gum with another long piece of spotted gum on the upstand behind the sink. Behind the stove (which is the only place that the real concern about grotty grout really comes into play) we have a stainless steel splash back going up to the rangehood. Not sure if this helps but I am thrilled with my kitchen and have no regrets about going with interesting tiles.

The size of the tiles is dictated more to the skill of your tiler. Some tilers prefer smaller as its easier for them to get the fall right. Using wastes that are linear like the grates make it easier as its straighter for them to cut the tiles. Having round drains do make it harder to tile a fall in the floor with larger tiles but now days there are so many choices with the waste options for the shower spaces that it allows more choice in sizes of tiles. What size shower are you wanting to go? Will it be more like a 1000 x 1200 rather than the standard 900 x 900??

I am just wondering whether it is a good thing or not to go with solid colours like the dark blue (prussian blue), grey floors and white on other walls all in tiles. I see that a lot of designers seem to do a pattern on one wall, but I haven't found one suitable and whatever I do, I just don't want it to look out of date in 5 years time. I am not sure how about much of the prussian blue tile is appropriate in order for it to be noticeable but not too overpowering.

I'd just live with it, paint the walls and vanity your sage green. My decision would be based on the fact that getting rid of the pattern is either going to be extremely time intensive or $$ intensive for not much gain. You can leave that pattern and update the bathroom easily by painting walls and vanity. The only way to get a nice finish on painted tile is to have it resin coated professionally. It's not cheap. With a stone toned bathroom it's always going to look dated because that colour way has been out of fashion for about 30yrs anyway. Best to just update cheaply and refresh the whole bathroom once it's no longer servicable. You spend on average 30mins a day in the bathroom. If it's neat and clean that's good enough. Close the door on it after use.