What the military should look at with such things as the Hercs, is to sell them to a UK freight operator at a lower price than market value for civilian freight hauling operations, and get them put on the UK register.
Thus having them available as a reserve uplift capability if the need arises in case of war or other operations, RAF crews could then cross train / operate them on a part time basis as and when required...etc
To much thinking out of the box?
Think about it, the Berlin lift was carried out with pulling in ex RAF transports from civilian companies, so this would be similar, as indeed some of the Voyagers are farmed out to airlines..
Heck, the RAF could then by back some freight operation hours from the civilian company when they are more cost effective than the other RAF fleets.