Bose, you are correct in stating that flight is prohibited unless you abide by the regulations:
Flight from, into or within the Restricted Area is prohibited, except for those aircraft listed below adhering to the regulations as listed
But the regulations listed make it quite clear, in my view, that ability to be able to squawk a discrete code is required (even in the circuit). The only exceptions appear to be balloons, hang gliders and para gliders:
How to use the restricted zone
As to NATS being able to cope with the amount of demand it is likely to receive, I quote the following from the CAA:
The simple answer is no-one knows the activity levels in class G.
Over the past few months we’ve been doing work with QinetiQ to try and get some kind of baseline figures which has been useful but needs more work and there is a proposal that one day this summer everyone is asked to file a VFR flightplan to get an idea of the demand.
NATS is working on its plans for what capacity will be available in the restricted area and they’ll publish that later but they have said they will be putting significant extra resource into AFPEx during the period and there will be extra ATC resource.
Regards, jez