[10] He also competed in a tournament at Radyr Golf Club which served as the Welsh section qualifying event, but which was open to all PGA members.

The final day was played at the Royal West Norfolk Club at Brancaster with Mayo ending up the winner by the overwhelming score of 14 and 13.

[20][21] In 1908, Mayo was paired with George Duncan and won a challenge match against Harry Vardon and Ted Ray.

[3] Mayo was demobilised in 1919 and returned to Burhill after serving in the Royal Air Force (RAF) during World War I.

[23][24] Mayo's younger brother, Walter, was Charles's assistant at Burhill from 1911 to 1914,[5] although he spent the summer of 1912 as professional at Baden-Baden.

[6] On 20 April 1920, Mayo and his wife along with their two children – daughter Ivy and son Charles, Jr. – departed Liverpool aboard the SS Vasari and arrived in New York on 4 May 1920.

[21] Later in 1920 Mayo took a job as head professional at Edgewater Golf Club in Chicago, Illinois, where he and Chick Evans lost a match to the touring British duo of George Duncan and Abe Mitchell on 26 July 1921.

[29] He subsequently accepted a position as head professional at Druid Hills Golf Club near Atlanta in December 1921.

[31] Mayo's appointment at Druid Hills was short-lived since he gave up the post and had returned to the United Kingdom in time to play in the Glasgow Herald Tournament in early June 1922.

In early 1923 he returned to the United States to take up an appointment at Westhampton Country Club on Long Island, New York.

[34] Mayo competed in the 1920 PGA Championship[14] and started out in round one of the match play tournament by defeating Lloyd Gullickson 2 and 1.

= unknown R64, R32, R16, QF, SF = Round in which player lost in PGA Championship match play "T" indicates a tie for a place Yellow background for top-10