For the first part of the class, Amanda had to take Harry's saddle back off again to allow the three judges to assess his physical conformation, putting marks on a scoreboard that was visible to spectators but not to the riders.
Each combination was put through a ridden workout - to a plan given out just before the event and that Amanda had not arrived early enough to memorise.
"I had to learn it by watching the riders that went ahead of me, and hoping they didn't make a mistake. We hadn't had time for a warmup but Harry went out and did a good workout, topping it off with his wonderful gallop, which is his forte."
When the results were tallied and Amanda heard her name and King of Hearts called as first placegetters she was delighted.
"It's so cool - it's our local show and the Beamish Salver usually goes to an outsider. It's such an honour to have won it over the other amazing show champions."
She has been especially touched with how many "gorgeous phone calls and emails" she has received since the win.
"People are telling me we looked an absolute picture, and were a delight to watch. It's such a good feeling. Showing horses is a tough game."
Tougher still since Harry, a thoroughbred by His Royal Highness, was never destined to be a show horse.
"Harry was a racehorse until he was seven, racing on the flat and in steeplechase races.
Then we bought him for my husband Johnny to hunt on. He hunted one season, then in the middle of the show season I lost my good show horse in a paddock accident.
"We'd decided Harry needed to do more than just hunt, so I took over the ride and took him to his first shows." Within three shows he had qualified for last year's Horse of the Year.
At HOY, Harry promptly won the Rising Star class and Saddle Hunter of the Year - a supreme title, qualifying him to compete in Australia last December, representing New Zealand.
While the Australia campaign didn't net the pair any titles, Amanda says the experience was hugely valuable.
"Harry was awesome over there, foot perfect, and I learned a lot. Taking a horse overseas by plane was an education."
Two weeks after they got home, Harry and Amanda were out on the show circuit again, using the added experience to take out Champion Hunter at the national New Zealand Horse and Pony Show. The hard work had paid off. Harry had qualified for Australia again.
Then came a third placing in the final lineup of the six top show horses at HOY 2016 and "then he had a big holiday!" says Amanda.
"He'd done so much we decided to turn him out for a break, instead of hunting him."
Back in work again Harry brought home the Beamish Salver, and won both his classes at the Gisborne Show and will compete at CHB's A&P Show.
"We will be doing dressage on Thursday and hunter classes on Friday."
Harry's preparation starts the weekend before, with trimming mane, tail and excess hair.
He will be washed, white "socks" whitened until gleaming, hooves polished and saddle and bridle made spotless.
On the morning of the show he will be ridden, massaged and have makeup applied and his mane plaited.
Amanda herself has to get "glammed up". It all takes time and skill.
"It's so hard to explain 'showing' to people who don't compete," says Amanda.
"It's hard work, but the result is a picture of grace, beauty and elegance. That has to combine with a horse with excellent physical conformation, better than average movement and the ability to perform under pressure. Harry has spunk and character - all the best ones do."
Next year's Australia campaign will be in Sydney - three shows including the Grand National, Sydney Royal Show and Kevin Hansen's EquiFest.
In the longer term Amanda is making noises about retiring and being on the sidelines as her daughter competes.
"I have competed since I was seven or eight. My daughter is seven now and I can't wait for her to get going."