The incidents, which occurred between November 20 and 22, saw drones spotted over RAF Lakenheath, RAF Mildenhall and RAF Feltwell.
Rookie number 10 Prendergast, who was making his first Test start for Irelan, was sent to the sin bin in the eighth minute.
Wales slumped to a 12th successive Test match defeat and head coach Warren Gatland saw the pressure ramped up on him as world champions South Africa won 45-12 at the Principality Stadium. For the ...