The British Driver with the most F1 wins is Nigel Mansell with 31.
5 Times, 1954, 1955, 1956, 1958 and 1965. He is tied second for most wins in the event.
His most famous achievement was his 1969 Open Championship, and 1970 US Open Championship wins.
Roger Federer with 15 Grand Slams
There is no such tournament as the British Open do you mean the Open Championship?
Nigel Mansell with 31 F1 race wins.
Yes, an amateur would win the Claret Jug if he won the Open Champoinship. However, he would not win the prize money, as that would contavene his amateur status
Louis Oosthuizen won the 2010 british open