"We sat down and wrote out a one-day excursion out to Whangarei Heads, with a strong Maori cultural influence," recalls Rangi. "But the timing wasn't right, because my career as a sales and marketing manager started to take off at the Advocate."
Rangi continued working at the Advocate while starting their family, which grew until they had five children - one of which was famously born in the Advocate toilets. During this time, Merv held the fort on the home-front, raising their children. After baby number five, Rangi left work and 'got to be a real stay-at-home mum for the first time'.
It was a trip to Hawaii which stirred up their earlier vision. There, Rangi met a shuttle driver who was a native Hawaiian. He confirmed what she already knew - that you cannot say you have truly experienced a country until you have got to know the real people of that country.
"By that I mean indigenous peoples. I was so touched by meeting this guy that I took my whole family and grandma over to meet him and his family and they hosted us for a month in 2013."
The experience rekindled their dream of a one-day tour but they realised they needed to make it more genuine and personal like their Hawaii experience.
"Our tour gives an insight into who we really are and what we are about. We are so much more than haka and pois, just like Hawaii is so much more than beach, surf and hula." But you will only experience true Hawaii through its indigenous people.
The name Tu Tika means 'Stand True' derived from Te Reo ote Omeka - The Mangakahia Morehu Brass Band, the family are members of.
"A command is given by the drum major to move into the stance of Attention. We stand strong and true about who we are, our culture and our beliefs. The name of the business reflects what we are about," explains Rangi.
The five-hour tour begins by picking up the tourists and taking them to the Harding home, where they are greeted with a traditional powhiri/welcoming ceremony.
This is where Merv's former career as an international Maori performing artist ambassador, and delivering the Maori cultural shows at the Auckland Museum, comes in.
A home-made morning tea is followed, before taking part in Maori mythology, weaving, waiata/singing and other traditional activities and preparation of the hangi. While the hangi is cooking, tourists are taken on a journey, visiting some of Whangarei's iconic attractions where the Hardings share the stories of Aotearoa through their eyes before returning home to enjoy the hangi. The day is concluded with a traditional poroporake/farewell ceremony before returning the tourists to their pick-up point.
The Hardings knew that opening their home to outsiders would also involve 'opening their hearts for the world to see'.
"We have absolutely nothing to hide - well only our bedrooms," laughs Rangi. "It's a mission keeping the house clean and tidy for visitors so we need to throw all our junk somewhere not to be seen. But, otherwise, our home is our visitor's home once they have been welcomed in, and then they become whanau.
"We are hoping they will take home a real connection to our whanau and home, which encompasses a better understanding of our people, our culture and our home.
"We believe Whangarei and Northland are the untapped jewels of, not only Aotearoa, but the world. Visitors flock here for our beautiful coastline and scenery - wait until they really connect with our people. Then, and only then, will the world know what's truly unique about Northland. He aha te mea nui o te ao? He tangata, he tangata, he tangata. What is the most important thing in the world? It is people, it is people, it is people," translates Rangi.
She describes an experience with her family 'like you've just scored a seat at the Mad Hatters tea party'.
"We are authentic, a bit crazy, funny and with stacks of love."
Their children - Rangimarie, 12, Stella, 11, Anahera, 9, Rakena, 7 and Manuao, 3, are their biggest supporters - "even though they get shy sitting in our van with a big picture of their father doing a pukana (to stare wildly and dilate the eyes) on the back".
"Their friends think Merv is Maui with his big fish hook. They know mum and dad have worked hard and we've all had to make sacrifices - for the kids, this has meant having to give up a number of their sports this year. They are a big part of this journey we are on and really want to be involved. We're so glad they are all proud to be Maori and promote our culture positively. We hope this empowers them to follow their own dreams."