Richard Davidson made a Facebook invite for his birthday and hit "send all', accidentally inviting hundreds of people including Wade-Brown.
He didn't expect her to show up, but was surprised to find her walking up to the house with a bottle of wine, having left Waitangi Day celebrations to attend the party.
Monty was impressed, saying a good mayor needed to be "nice, like if they get invited to a birthday they need to respond".
He said Wade-Brown was "very polite".
When he heard through his father she would not be standing for mayor again, he asked whether she would be able to keep her mayoral chains.
"Daddy sent me a photo of her with the mayoral chains and I wondered if she was giving them away, and she was."
With the help of his mother, who operated the hot glue gun, Monty constructed some new mayoral chains for Wade-Brown with chocolate coins, then presented them to her during a special visit.
Monty had asked if he would be able to say goodbye to Wade-Brown before she left the mayoralty, so his father, who is a compliance officer for the council, teed up a meeting with her.
Wade-Brown organised an afternoon tea, at which Monty handed over his creation.
"She said that it was very cool and she probably wouldn't eat them."
Wade-Brown told the Herald: "This work of art is definitely ephemeral, which means it's been eaten."
After being informed of this, Monty was curious to know if the chains were "yummy".
The family also gave Wade-Brown a few other small presents as a farewell gift.
"Her favourite colour is hokey-pokey," Monty said.
Mother Nikki Davidson corrected him, saying it was "orange". Monty had noticed the colours Wade-Brown wore most often in photos and on TV and wanted to get her presents in those colours.
He was interested in who the new mayor would be, and said he liked Justin Lester.
Wade-Brown said Monty did an "excellent job" making the chains.
She said he was "charming" and "polite", but "yeah, quite a healthily mischievous young man".
