The former international showjumper, who is 51, has been having treatment for cancer. He has four children.
BS said Michael kept guests “laughing throughout” the celebrations with his “inimitable style”.
Pennie Cornish, owner of Hickstead Derby winner Caritiar Z, dedicated Sunday’s win (23 June) to Michael.
“This one’s for Maccy,” she told reporters. “Get well soon.”
This news story was first published in Horse & Hound magazine (27 June 2013)