Hello there. We're have share of the freehold for a Victorian conversion, which is two flats (one ground floor and another a two floor maisonette). The only communal area is a 4x7ft hallway which houses doors to our flat and the staircase which leads up to the maisonette. 

We're looking to sell our flat and have been informed we'll need a fire risk assessment for this area. Given it's so small and looking online we felt we'd probably be able to do the assessment ourselves, but just wanted to clarify a couple of things. Would all doors in this area need to be fire doors? If a door doesn't have a specific marking, is there any way to tell that a door is in fact a fire door? 

Would imagine we'd need a smoke alarm for this area, but other than that would there be any other reasonable requirement? There's no real risk of fire, so would imagine an extinguisher given the small amount of space would be excessive. 

Your answers are in this guide:
https://www.cieh.org/media/1244/guidance-on-fire-safety-provisions-for-certain-types-of-existing-housing.pdf

Particularly of use will be Section 37. Buildings converted into self-contained flats on page 46.

If you can prove that the conversion was after 1991 and had full Building Regulations Approval as meeting the requirements of Approved Document B then different guidance would apply.