If you sell these off then the buyer will want a return on their investment, by which they introduce charges where before they didnt exist, or hike up existing charges.
In the case of Defence Storage and possibly Oil Pipes +Royal Mint (not sure) the main customer is the state,which only means that the state will end up having to pay more to use the service they had on the books already, and so cancelling out the saving.
of course this is true of all the PFI privitisations - they have ended up costing the state more. Railways being the classic example - according to train expert Christian Wolmar the state pays four timese more than it ever did under British Rail (factoring in inflation) - and customers pay so much more too. (£10 for a travelcard? scum)
Dont these fuckers learn? Shit, theyll be consolidating their debt into one easy payment at this rate