Sadly, the jobsworths that inhabit T5 at LHR wouldn't let you through "compliance" with less than 35 mins to go now.....even if you are 10 metres from the aircraft.....rules don't ya know.....
I can understand it in a commercial environment when dealing with millions of pax passing throgh a terminal. I find it harder to justify when dealing with a military machine with different needs.
It would appear that there are always people pulling in the oppsite direction to everybody else?