Annex F is an informative Annex and therefore for information only.
The Annex is there to provide one way of assisting the design in determining the spacings and mounting heights of VADs. It is additional guidance only, not part of the recommendations of the standard.
As long as the recommendations of clause 17 of BS 5839-1:2013 are followed, then a system will be deemed to be compliant to BS 5839-1 and a valid certificate can be issued.
Manufacturers provide the best guidance for the correct spacing and mounting options for their own products and this guidance should be followed. As part of their certification to BS EN 54-23 manufacturers provide information for categories O, W & C