"He was pretty useful but I knew he wasn't going to be a grand prix dressage horse," said Weal. "He's done a lot of mileage on the flat and while he used to be difficult in big atmospheres, now he just loves it."
Weal got a call from Burton last week and scrambled to find a ticket from New Zealand in time to see them go.
"It's just amazing to have such belief in the horse and see it come through."
Meanwhile, Nicholson finished on his dressage score of 43.6 penalty points. He was 13th after the dressage phase, moving up to eighth after going clear and inside time in the showjumping, and then up to fifth after again finishing the cross country hoof perfect.
Equestrian Sports New Zealand high performance director Sarah Harris said Nicholson's efforts were "just magic".
"Nereo made the [cross country] track look easy and looks fit and ready to go for London. Andrew just loved it," she said.
Olympic reserve Lucy Jackson and Kilcoltrim Ambassador were the next best-performed Kiwis with their 22nd place finish. They too pulled themselves slowly but carefully through the field throughout the event.
They were in 36th spot after a 57.6 in the dressage, moved up two places after adding four faults to their score after dropping a rail in the showjumping and then finished on 70 thanks to adding just 8.4 time faults from the cross country.
Results -
Individual CICO 3 star: Christopher Burton (AUS) Underdiscussion 38.8 penalty points 1, Michael Jung (GER) La Biosthetique-Sam FBW 40.6 2, Laura Collett (GBR) Rayef 40.6 3, Sandra Auffarth (GER) Opgun Louvo 41.6 4, Andrew Nicholson (NZL) Nereo (owned by Deborah Sellar) 43.6 5, Lucy Jackson (NZL) Kilcoltrim Ambassador (owned by the Sprout Syndicate and Jackson) 70 22, Jonathan Paget (NZL) Bullet Proof 104 32, Mark Todd (NZL) Flintstar (owned by Darnelle Hubbard, Tim Price and K. Gray) withdrawn before cross country. Mark Todd (NZL) NZB Grass Valley (owned by New Zealand Bloodstock and Todd) withdrawn before cross country.
Results -
Nations Cup: Germany 136.40 1, Great Britain 141 2, Sweden 176.8 3, New Zealand (Andrew Nicholson, Nereo 43.6; Lucy Jackson, Kilcoltrim Ambassador 70; Jonathan Paget, Bullet Proof 104; drop off score Mark Todd, NZB Grass Valley 1000) 217.6 4, France 233.6 5, Netherlands 304.6 6, Australia 1,126.6 7.