I think the bottom one in brushed stainless steel. As you say if no wood then why accentuate that with an oak threshold strip. I have brushed stainless steel at the junction between an oak floor and a neutral carpet. I think it looks much better than a thick oak threshold strip. I have oak doors too. I would opt for the 25mm version as the 14 leaves very little tolerance for neat finishing. Just measured the width of mine, they are 25mm. Finish is very tidy.

Thank you all! You've made a fair point Jonathan. If the mirror is lined up with the top of the door frame then it can only be raised by 2cm, which will mean a gap of just 8cm above the console. The gap from the console to the actual ceiling is 164cm and the mirror is 120cm high. I was planning on having the mirror 15cm above the console but that will then sit 7cm above the door frame so now I'm confused 🙈 I would appreciate no comments on the console or mirror needing to be changed as I'm really not in a position to do this now so I appreciate your advice on just the height of the mirror please. It definitely looks far better and less lonely in real life than in the pictures ;) Thank you!

Problem with bar height stools they aren’t comfortable for working for long hours. Will be fine for an hour or two.

I think you should investigate what the minimum height is first. I know of cases where people have raised roofs and lowered floors decreasing the ceiling height below. Anything is possible with planning and a healthy budget. Why not get a few loft conversion specialists to come and discuss the options. It's early days.