After the war, Joe Potts established a leading motorbike racing team and became Norton engine tuners of some renown so it was a natural progression to move into 500s.
Joe, Comish Hunter and Pat Prosser all purchased Cooper Mk IIs in 1948 with the intention to kick starting motor racing in Scotland as had already happened in England. Joe fairly quickly showed himself to be the best of the three winning at Bo'ness in September. He was second to Colin Strang at Bo'ness in June'49 and fastest at Rest and be Thankful in July and again at Bo'ness in September.
Joe retained the Cooper for the early part of 1950 travelling down to Silverstone in May for the Grand Prix d'Europe where he managed eighth in his heat but did not feature in the final. At Bo'ness in June, he was beaten by Comish then gave his own JP its debut at Rest and be Thankful where he was third fastest to Comish and David Swan. He failed to finish at Winfield on 21st but could take some consolation that Hunter, now also in a JP, had taken second to the JBS of Peter Collins.
Potts used the latest version of the JP for 1952 starting with a third at Charterhall on 6th April, third again at Turnberry on 3rd May He fell ill shortly after this and missed the majority of the season, thereafter he concentrated on trying to develop the car, experimenting with De Dion suspension to no avail. Eventually he retired to concentrate on the bike racing.