We have just completed a periodic I and T of an 80 bed accommodation block for students. On chatting to the estate services chap, he was surprised that I merely mentioned that AFDDs were a current regulatory requirement but did not issue a code 3 as had been the case with other contractors in other parts of the estate. 
I really do not understand how a contractor can make a recommendation to install these things in an existing building without detailed knowledge of the fire risk. By all means point to the regulation, blunt and all as it is, but leave the recommendation to the fire risk assessor.