I don't know what shipping would work out at, but all the
L'aunsport bits I've seen are by far the best quality replica WRC parts.
You'll need to trawl their online store to find the mirrors (or just drop them a line), but their website shows the correct classic "high" WRC mirrors on
one of their replicas.
EDIT: I just saw your foot note that you are looking to spend less than £400: I think you'll be lucky, but check the site!