After a disastrous renewal when my FAC came back partially revoked and various items left off, my confidence in D&C to maintain their previous high standard of service has been dented. AFAIK a new FLD manager with little firearms experience, plus other staff changes with more to come, doesn't bode well for the future.
you must challenge this and not accept the FAC
revocation of any level is something you will have to disclose on renewal/variation
omission through incompetence is not an excuse
put your reluctance to accept the document in its current form in writing to both the head of the firearms unit AND the chief constable.
to the OP:
numbers of rifles is irrelevant, as is their classification as "deer legal", as is your police authority location. This is a National HO Guidance that the authority must adhere to or be held accountable and detail why they feel they are "special"
As with any addition or variation, justification must be clear and leave no room for interpretation or opportunity for police rejection.
look towards detailing bullet weights, trajectory, specific scopes you want for specific purposes
use the humane killing aspect of increased accuracy potential of a flatter trajectory (yes I know its ********, but no-one argues with the "i need to kill the deer faster more humanely" argument!), more energy, faster bullets, shorter barrels etc etc
I have .243, .308 and .270 (among others)
the bullet weights barely overlap 50-100gr, 100-150gr, 150-200gr
I see no issue whatsoever if you get all your ducks in a row and present a valid and wriggle free argument (buying one so you can retire the others long term is not one of those BTW)