Mirror doors can be function over style so not specifically a trend option. If the room over all is a quite on trend then the reflection will be a picture worth replicating or add wallpaper for a fun feature or even keep to simple and the same colour as your walls as to not highlight the doors.....a few options there, that may work for you.

with a wall cabinet almost 4 m wide i would expect to have at least 9 doors each over 440mm wide?? and with only 3 doors or even three pairs of doors you would have to step backwards to open the doors and they're much too wide and heavy ...how deep is the vanity below the wall cabinet and is the wall cabinet recessed into the wall or wall mounted?... do you need this much wall storage for medicines and toiletries? combined with storage in the vanity an average wall cabinet 1200 wide (with three doors) should be more than enough for the usual collection for one person ...consider a recessed wall cabinet say 2400 wide with six doors and the balance of the wall with fixed mirrors ..you need to talk to the builder and/or cabinet maker to decide what suits your needs

have a shorter recessed wall cabinet for storage and if necessary have the balance of the space fixed mirror.....you should find something suitable at a fraction of the cost of custom made but strongly suggest that you don't have the vanity hard up against the glass screen (a gap is useful for hanging a hair dryer or hand towel and allows easier access to clean the glass screen) we've been disappointed with custom made vanity and wall cabinets which were more than twice the price and no better quality

Thank you all who replied. I love the top picture in Julie Herbert's reply. I'd love to know how that look was achieved. Frosting film also looks good. My husband suggested painting, oklouise, but I read that it would just peel off glass. Good to know you've had success. I think I will try the trade-in approach initially and see what the cost would be, as my preference is smart-robe timber doors that match the wall colour. They are less obtrusive than mirrors, which seem to dominate the room and reflect all the things I prefer not to look at (Like myself first thing in the morning!) Fortunately, the existing doors are in perfect as-new condition.