I'm also buying this cylinder cover...

Hello. If you're still looking for the right letterplate we have one that would work with the lovely clean lines of the door you posted. It's £119 with next day delivery, made in the UK from marine grade stainless steel and guaranteed for 10 years. Link to shop.

Either of those letter plate would suit. Kirkpatrick is a good quality brand.

As an alternative you could consider a letter box on the wall. They have keys to open and close so are secure. Saves any draught around the letter plate.

I think the first one will go very nicely with your door! Nice clean lines which won't distract from the glass pattern.