The photos to me are glaringly obvious that there is drug abuse active in these flats, that is all I need to take from the photo unless you disagree with that evaluation?
Some of the points you raised were reflected in my later posts, the OP posted a picture of the type of tenant we may expect could be in these premises, now give the council recommendation was LD3 I do not believe this reflected the nature of the tenants unless there was info' that hasn't been disclosed here. In reflection of the possibility or probability that tenants are drug users etc then the system installed should reflect the added issues that this comes with.
I cannot vouch for his local building control I'll give you that nor can I know how they gauge their requirements but I can give an informed opinion on recent systems I have installed in HMO's where this is a typical type of tenant and I have fitted a system I suggested which reflected the higher risks associated with the tenants behaviour, since fitting this system 6yrs ago there has been 2 fire events caused by tenants on drugs which were dealt with fast and efficiently with no loss of life and just minor property damage, it was the fact the system was a mix of LD1 overlapping a grade D system to the flats that the tenants got out in the effected flat, an LD3 may have seen loss of life to those in the effected flats had they not had there own independent system installed.
PS - cheers for expanding on your disagreement, it is nice to know other members opinions be they negative or positive, this is how we learn, I am a stickler when it comes to members hitting disagree then posting nothing unless it is clearly obvious exactly what you are disagreeing with, in this case I needed more info so hope you understand me calling you out on it.