Have you already sourced your tiles? I would expect most tile stores could help you find the edging tiles which I think are typically termed 'pencil' tiles for the style you have shown. We used bevelled subway tiles in our DIY ensuite. In hindsight we would have aimed to finish the brick pattern with 1/3 and 2/3 sized tiles (like in your pic 1) rather than full and 1/2 (pic2 and 3) to give a more even edge thickness/profile... Might not suit and we didn't use capping tile (I lost that arguement!) so it is probably more obvious in our bathroom, but just something you might like to consider.

I think the interior design team is the same one who did their Sydney restaurant - they are not on Houzz but their name is Meacham Nockles McQualter. Might be worth a quick email to them to see where they sourced from.

Thank you all for your reassuring comments. I agree, in the midst of building you're in the 'zone' and small things can be made out to be bigger things. I guess it is all about expectations - expecting one thing and getting another. I now feel more content with the finished feature wall, based on all your comments. Many thanks!

Where are you located? I have seen these at cerdomus tiles in Richmond and Moorabbin tiles in Moorabbin if you are in Victoria.