Geddie made his debut in the British GT Championship in 2010 with Trackspeed, joining David Ashburn for the third round of the season at Knockhill. Geddie returned to the team full-time starting at the Rockingham round, the pair took four victories to secure the championship for Ashburn and second place for Geddie. For 2011 Geddie raced a Ferrari 458 Italia for CRS Racing alongside his dad Jim; the pair started the season in an older Ferrari F430 Scuderia GT3 while they awaited delivery of the new car. The pair went on to win the championship by 14 points over reigning champion Ashburn despite a best result of two-second-place finishes at Snetterton and Rockingham. The Geddies only competed in one event in the 2012 British GT season, racing an Apex Motorsport run McLaren MP4-12C GT3 at Silverstone where they finished fifth. Geddie joined United Autosports for opening race of the 2013 British GT season at Oulton Park, substituting for Rob Bell in the No. 23 McLaren alongside Zak Brown. Geddie returned to the team at Snetterton, partnering Jody Firth.
(key) (Races in bold indicate pole position in class) (Races in italics indicate fastest lap in class)
(key) (Races in bold indicate pole position) (Races in italics indicate fastest lap)
‡ Guest driver – Not eligible for points.