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.
IIRC there was a survey about 6-8 months ago where qinetic were asking about our movements in Class G. At the time I filled it in but commented that it was only looking at people based at airfields in the SE. If you were based elsewhere it only wanted to know about your flights in your local area. It would be impossible to respond to the questionnaire for flights into the SE.
It would appear my fears about that survey were more than justified and the data seriously misused.