As an amateur, Guy represented Berkshire, Buckinghamshire and Oxon at every level and was a member of the 1st team for 5 consecutive years. He shot three course records and was club champion at two clubs, Windlesham and East Berkshire, with record aggregate scores.

In 1998, Guy achieved a notable success in The Prince of Wales trophy in Kent against an exceptionally strong field. Guy stormed home to victory by a clear four shots to beat a whole host of top national players.