The Queen's granddaughter was not only bemused because Yorkshire-born Mike had not planned on the extravagant buy, but also because he knew nothing about the horse in question.
Luckily for Mike, however, his spur-of-the-moment purchase has worked out rather well and Monbeg Dude came out on top at the Welsh Grand National in Chepstow in 2013 and has gone from strength to strength since.
"I like to bid in auctions without meaning to actually win things" Mike explained. "I only went for a bite to eat and a night out.
"No horse had gone for less than £28,000 so I thought my first bid of £10,000 was pretty safe, likewise when I upped it to £12,000," he added. "I knew nothing about the horse, hadn't checked the brochure and couldn't see the Dude as I was sitting with my back to the sale ring."