Twiglet1 - There are so many variables for different operators and different airports that it was always difficult for UK CAA to come up with a definitive answer. Some airports have a very slick security/bag drop such that it is not punitive to use the airside crew room as the reporting point, others less so; hence it was down to the operator to consider all the applicable conditions and define the reporting time accordingly. In the event that on the day delays mean it takes longer than standard report then crews should delay the departure until all pre-flight duties are completed correctly and report the occurrence, and reasons, through the SMS. Sufficient reports would flag that a discussion is required with the regulator.