Now they're neighbours, with Mailo renovating and painting the former National Bank office to create a bright white space of her own.
Prior to her move south, she worked at natural health and beauty boutique The Tonic Room in Kingsland for seven years.
"I actually had really bad acne before I took that job, and when I started there everything flipped for me.
"Things changed into the more natural side of things compared to what I was using before. The beauty therapy world is actually really toxic, it's full of fillers and really bad chemicals."
Mailo, who is also a trained yoga instructor, said The Slow carried on that natural beauty journey, and the facials she provided were more than just a "little tickle".
She offers a range of different options, ranging from 45 to 75 minutes.
"My treatments are really intuitive, I guess.
"Something like the holistic facial looks at people's beauty wellness - what they're eating, what their stress is, and what's going on internally.
"Then there is the slow facial, which is really calming. It's a way to relax and lower the heart rate. It's almost like a yoga session in a way."
As for Whanganui itself, Mailo said she had never been to the city before looking for a house.
"The first time I came here was to go to an open home.
"My husband is from Palmerston North so we were looking there originally, but I just couldn't do it. I needed to be by the coast.
"Me and my daughter came over, drove down Victoria Ave, and everything was just so pretty.
"The first interaction I had was with the most friendly guy at Caltex, and that's what sold me, I said 'I want to live here'."
The family bought a house in Castlecliff, meaning Mailo got her wish to be close to the coast.
"I want to cater to everyone, from people who want to come in regularly and want to buy top shelf products to those who pop in every six months to treat themselves.
"The doors are open to anyone."
The Slow, at 98 Victoria Ave (second floor), will open on November 22.
