The issues were that the only route to the runway (due to wingspan) requires 9 stands to be closed and a massive exercise with closing roads etc. After pushback it takes at least 15 minutes to stow the towbar so the taxiway is blocked. It then will take a minimum of 15 minutes to taxi for departure. Once lined up, the takeoff procedure involves running all engines at high power for at least 5-6 minutes prior to brake release. We have been given approval for an 0900z.