Hi,
I think you have misunderstood the point I was making. The height of the Dali Fazon sat speaker is around 9" when using the stands. When you rotate the sat to use as a centre speaker, if you do, the height of the speaker remains around 9" due to the design of the mount.
The B&W speaker, when rotated, is lower in height in relation to the left and right speakers. Check out the pics in the review here: http://www.whathifi.com/review/dali-fazon-3-51 you will see the centre speaker is rotated.
If you compare the centre speaker height with the B&W from this review picture: http://www.whathifi.com/review/mt-25 the height of the speaker is almost half of the other 4 when it's rotated.
All this is relevant only if you intend to use the stands.
If you wall mount, placement should be approximately ear level while seated. You will have to judge where the speakers will fit in best with your own living environment.
Cheers,
Cofnchtr.