Red Four
The areas you refer to are not covered by this announcement. The airport business, which is the competition you refer too, is a separate and totally transparent part of NATS. Their costs are 100% covered by the money they get from the airport authorities or owners. As this is on a contract basis, there is no fall in the level of money paid there.
The area which is being funded is the NATIONAL part of the system, the En Route division. This division is regulated by Government statute under the licence issued in the PPP.
All in the blurb which came out before the PPP happened, and well worth a read, but too late to protest about the flaws in the plan.