Last year Boon, 21, won in Germany, where Britain also took the team title. His form has continued with victories in the national championship and the Land Rover final selection trial.
Boon, who groomed for Funnell at Blenheim two years ago, will be having his first ride over the Oxfordshire course, on the 10-year-old Vital Decision, who usually gets good marks in the dressage.
Sarah Cutteridge, the only other member of last year's team competing, proved her talent against senior riders earlier this month when jumping a clear cross-country round on her first sortie at Burghley. In the senior international section, Karen Dixon, who won team gold and individual bronze at the World Games, will ride Hot Property, the nine-year-old grey withdrawn before the cross-country at Burghley.Reuse content