Peter
The first consideration should be which fire safety standard should be applied in this case. It sounds as though the standards for a house in multiple occupation(Housing Act 2004) are appropriate rather than the standards applied to flats- the fire officer and environmental health officer should be consulted to find out how they are viewing it.
It reads as though each flat has its own stair- this is a little confusing. If there is a common staircase serving several flats then the first priority will be to ensure that a fire in any flat as far as possible cannot affect the means of escape from the others- by providing fire doors and screens to the staircase- they need to be to the FD30 S SC standard. Depending on how many staircases and how many floors there are there may need to be additional protection.
As for alarms this will depend on several factors- the height, the number of staircases, the level of structural protection that can be achieved.
Finally to the heart of your question. If it were flats in the middle of town you are right that call points will attract vandals like wasps round a jamjar. If it were a HMO the standard is for a full BS5839 system that includes break glass units on each floor and detection in each room leading onto the staircase. If its flats then stand alone detection to part 6 and nothing in the common areas would be the norm. However if the means of escape can never be brought up to the standard where its protection can be guaranteed in case of a fire in a flat then its likely that the fire officer has asked for detection in the common areas to give early warning of smoke in the staircase - to alert people before they are cut off. In the circumstances you describe the manual call points may not be a problem. If they are likely to cause problems some could be omitted under a declared deviation to the code, by agreement with the enforcement agencies - the spec under BS5839 would probably be L4 in this case.
Now we all know this solution for flats would bring problems- people would be reluctant to evacuate if the common areas alarms operated. But can anybody come up with an alternative idea in this case?