Some fire doors where I work have no push bars on them and have bars and bolts on them in working hours . Someone as complained about them being used as an entry and exit so bars and bolts are on all the time is this illegal and if so is there a legislation I can mention?

Not all exit doors require panic push bars they are usually used in place of public assembly but can be used where considered necessary. All doors required for means of escape are require to be easily opened and available during the time the premises is occupied, bars and bolts are a strict no, no during working hours. The relevant legislation is  The Regulatory Reform (Fire Safety) Order 2005  and check out article 14.