Do I need fire doors?

[Jackie O]

Hi, I wonder if anyone could help. 

I have a small office, with 4 people regularly working in this office.  We do employ a couple more people on site but they do not have a desk in the office, and occasionally come in for a chat.  We do have a meeting room upstairs that can seat up to 10 people.

I have attached the floor plan.  I am being told every door needs to be a fire door.  The 4 office desks are split between room 1 & 2.  There is an internal door between the downstairs and upstairs.  However, there is a separate fire exit upstairs which leads directly outside and not used by anyone else.  As there are 2 fire exit points downstairs and one up stairs and the office is relatively small, do we need to also put fire doors on every room / up the stairs?

Thank you in advance for your help.

[green-foam]

Jackie O has posted again, with drawing. To see the post in full click HERE