We always use wallmount from Vogel's or Audipack, there are a coupole factors you should look at before buying one.
whats the Vesa (400×400 in your case)
weight of the screen (can the mount support it?)
and size of the screen (dont want the mount to show behind it)
If you wish to mount it flat against the wall, with out a tilt option, I'd go with the Vogel's PFW-5300