helicraig
your not a member of the hcgb [are you] so your wont be getting the hcgb price anyway
it seems to me the hcgb has managed to get a special reduction for its members arriving and departing when the commercial trafic has stopped or does not want slots anymore ,thats sound commercial practice that will reduce the cost of commercial trafic
your private flight is it cost sharing? if so will you will be paying your share to arrive twice and depart twice as both flights are classed as seperate flights for the cost sharing rules maybe least said the better