The III Grote Prijs van Danske (or 3rd Danish Grand Prix), was held on 25–26 August 1962, at the Roskilde Ring circuit, Roskilde, Denmark, the race was run over three heats, one of 20 laps and two of 30 laps, and was won overall by Sir John Arthur Brabham, was an Australian racing driver who was Formula One World Champion, he all three heats in his what?