Nice. Colours blend well and look fresh and love the big mirror

Why do you need any clear space at all ? The 'trend' for the last 30 years has been to have basins that protrude slightly forward -- yes , I know , there's arguments for and against , but basically if you have oval basins , there is space to have liquid soap dispensers or whatever other accessories you want , even if your vanity was say 1200 x 300 -- theres no taps , so I actually think your vanity sounds a bit too big visually ( or the basins too small , although at 550 any bigger would be classed as a bath haha ! ) .

. Colours scheme looks great. I don’t think there are any rules, but eclectic mix might be good for that vintage thrown together look. It may depend on how the fittings turn out and what you decide for sink and bench top. My thought would be to steer away from shiny modern taps. Here are a couple of pics for inspiration, one looks like it has similar fittings on cabinet to yours.

Harvey Norman are distributors for Timberline vanities which may have what you are looking for - see link. If you see one you like online, you can go to a HN Bathroom store and they can order it. https://timberline.com.au/