Unless the RAF aerodrme activates a TRA then its only 'protected' airspace is the ATZ.
However IMO poor airmanship to fly through a notamed display in the manner discribed - the CAA could try a prosecution invoking "reckless endangerment of an aeroplane" if there had been an incident.
The RAF does have a protected display practice area for the Reds - R313 at Scampton - why not use that?