Jimjams

Hi, I live in a retirement apartment complex of some 50 individual apartments. It is well run and is properly maintained and up to date with legislation. Apparently we have had a fire assessment by an independent fire risk assessment company who have said that a lot of alterations are needed to fire doors around the building in order to be compliant. This includes replacing all the brass hinges on all the doors with steel ones probably in the region of 50 fire doors and communal corridor doors and each one already has 3 hinges and they are even saying that individual apartment front doors (another 50+ doors , already with 3 hinges per door) need to have these brass hinges changed to steel as well. The building was constructed 30 years ago and has been regularly assessed for fire risk every year, and has to date always been compliant except for some new style emergency exit signage and new types of release bars fitted to exit doors. My question must all these brass hinges be changed retrospectively when they have been passed every year to date and have been 'compliant' up to npw, or is it that any new doors that are fitted have to be fitted with new compliant components to meet regulations? Any advice would be appreciated. Thanks.