Nana Jos, who has no grandchildren of her own, was delighted with her grandson for the day when the pair met at school today.
"He's very informative and polite, a delight to be with. I'm very proud of him," Nana Jos said.
Meanwhile Harry was just as delighted to have "an extra nan".
"I'm really glad she came. I love having a nana. I love it that Nana Nock offered, and that Nana Jos stepped in."
As he was showing his new Nan how to write computer code on a tablet he was already thinking ahead to next year and whether he could bring both of his stand-in nanas.
Harry does have a grandmother but she lives in the UK so he doesn't see her very often.
His mum's father, former Kapiro Garage owner Martyn Payne, died in 2015 and both his father's parents have passed away.
Riverview School principal Ken McLeay said about 250 people attended Monday's grandparents day. More than 30 had come from Auckland or further south and two had come all the way from Christchurch.
After an assembly and powhiri the children showed their grandparents around the school grounds and classrooms.
Nana Jos said she was amazed to see what children did at school these days and how classrooms had changed with the advent of digital technology.
"Gone are the rows of desks with flip-top lids."