The new guides are very sketchy about this Im afraid, and it only seems to mention that training should be undertaken "periodically, upon first being employed or exposed to new or additional risks, or as identified by your risk assessment"
As an Inspecting Officer I normally advise two fire drills are undertaken annually (to cover all staff - i.e. night staff and day staff) and fire safety training to repeated atleast annually to include evac procedures, door check procedures and the use of Fire Extinguishers.
So in short staff should receive training on first employment, when exposed to new or increased risk and then periodically.
Risk assess it , observe your fire drills to see how your staff cope / react , periodically quiz your staff to ensure they know what they are supposed to be doing and if you have any doubts instigate refresher training if you feel there are any problems. The idea is that you as monitor your own staff etc.
As a double check measure contact your local Fire Officer to see what s/he would accept.