Clarkin, who attended the 2011 wedding of the Duke and Duchess of Cambridge, has been rated an eight-goal player for years. How good is that? Well, polo's handicap scale extends from -2 to 10.
Since July, his passport has been stamped in Britain, Spain, Australia (twice) and India (twice). He and wife Nina - the former world No1 women's player who comes from her own polo-playing dynasty - try to base themselves in England and New Zealand for half a year each.
Likewise, Clarkin's cousin Tom Hunt is on a six-goal handicap in New Zealand and five in England. Handicaps are reviewed by a committee once a season.
Hunt's usual form of transport includes a saddle, but he's made the odd exception when it comes to punctuality between tournaments.
"In England, there's a lot of polo sometimes, so to make the next game we get the odd chopper ride. A guy I work for has his own chopper, so we jump in with him."
Hunt also revelled in a visit to Mala Mala Game Reserve on the edge of Kruger National Park during the drawn test series between New Zealand and South Africa last year.
"They took us on safari for two nights," Hunt says. "We saw the Big Five [elephant, lion, leopard, buffalo and rhinoceros] and a guide said it was the first time one particular pride of lions had been seen for years."
Clarkin and Hunt are not ostentatious about living a lifestyle celebrated for its glamour. Both know the dangers of the sport and the diligence required to succeed.
Clarkin's father (and Hunt's uncle) Paul died on the field aged 54 when he fell at Cirencester in 2004. He and wife Chele took John-Paul and his siblings around the polo world in their childhoods.
"Like any sort of job or career, there's always risk," Clarkin says. "In day-to-day life, it's about managing that for the best.
"I did go through a hard time after Dad's accident. He had so much passion for the game, and horses in general. He wouldn't want us to give up because of that."
Hunt also suffered an injury years ago which resulted in bleeding on the brain.
"I was representing New Zealand, had a collision with another horse and came down on my head. I was fortunate to survive."
Hunt started as a groom and worked his way up.
"I was born and bred into it. All my uncles played, as did my father. I didn't really have a choice. Not everyone does it that way but I had some good opportunities."
Clarkin and Hunt estimate ponies - polo refers to its thoroughbreds as 'ponies' rather than 'horses' - take anywhere from three to five years to train after being taken from the track as three-year-olds.
"They require a lot of riding in," Hunt says. "I've got 20 horses now, and some days you start at six [in the morning] and finish at six. Finals day at The Open seems glamorous, but a lot of hard work goes into them.
"They gain your trust at a young age but it's a slow process. A lot of mileage goes into them cantering slowly, with another horse coming towards them at a trot and you touch and then ride away. Over time, they gain enough confidence to trust you, and do it at a faster pace.
"There are no nurturing shortcuts. It can be tough from a business perspective, with freight costs high [to export ponies from New Zealand] but there are still people like me who take horses away and a handful come to buy them. If the right horse pops up, it's never around long."
Clarkin remains driven by the lifestyle which provides fulfillment, regardless of the toil.
"The exhilaration factor gets you hooked. We played on Thursday in some of the worst conditions in my life but had a bit of a chuckle about it. It's not bad for a day job. I could be in an office."
