How does one best assess fire safety requirements in HMOs

HMO Licensing

Hello,
I would be grateful if a fellow HMO operator could enlighten me. I am struggling to understand the HMO fire regulation requirements as the LACOR guide recommends certain fire safety aspects which are much more lenient than what estate agents and builders recommend. 
One of my properties has three bedrooms, is on two floors and is rented by three family units ( three young professionals, so altogether three people)  and therfore is classified in Camden as an "additional HMO". According to LACOR this house requires ( and has already installed) wired, interlinked smokedetectors in kitchen, livingroom and upstairs and downstairs hallway. 
An estate agent who viewed it said with certainty that the house requires a firealarm system and wired smoke detectors in all the bedrooms. A builder who attended said that I definitely need 30 minute fire doors. 
I am happy to install whatever is necessary to install, but it seems an overkill to require a fire alarm in a small three bedroom house ?
I have larger HMOs too and they all have firedoors and fire alarms but according to LACOR the size of house and amount of people in it influences the neccessary requirements. 
Can someone recommend an independent fire safety advisor or let me know where to find one, because any supplier/installer will automatically say that one needs everthing as its their business to sell their prodicts. 
Is the LACOR guide on the website the latest edition? Maybe it changed recently?
Confused and grateful for your advise.

Stella