He played at representative level for Great Britain and England, and at club level for Dewsbury, Cronulla-Sutherland Sharks, Bradford Northern, Leeds, Featherstone Rovers and Batley, as a fullback, prop, second-row, or loose forward, and coached at club level for Batley.
[3] Grayshon played at second-row in Dewsbury's 22–13 victory over Leeds in the Championship Final during the 1972–73 season at Odsal Stadium, Bradford on Saturday 19 May 1973.
Grayshon played at second-row in Dewsbury's 9–36 defeat by Leeds in the 1972–73 Yorkshire Cup Final at Odsal Stadium, Bradford on Saturday 7 October 1972, played at prop in Bradford Northern's 5–10 defeat by Castleford in the 1981–82 Yorkshire Cup Final at Headingley Rugby Stadium, Leeds on Saturday 3 October 1981, played at prop in the 7–18 defeat by Hull F.C.
in the 1982–83 Yorkshire Cup Final at Elland Road, Leeds on Saturday 2 October 1982, played at prop (replaced by substitute David Hobbs) in the 12–12 draw with Castleford in the 1987–88 Yorkshire Cup Final at Headingley on Saturday 17 October 1987 (he did not play in the replay), and played at prop in Featherstone Rovers' 14–20 defeat by Bradford Northern in the 1989–90 Yorkshire Cup Final Headingley on Sunday 5 November 1989.
Grayshon played at second-row in Bradford Northern's 6–0 victory over Widnes in the 1979–80 John Player Trophy Final at Headingley on Saturday 5 January 1980.