They like Whanganui's small size and want to be part of the community.
Both have national and international work they can do from here. Mrs Duncan's part-time job is helping churches in the Baptist Union of New Zealand link with their communities.
Mr Duncan - who has degrees in sociology, theology, culture and society - travels to lecture in New Zealand and Australia. And they have savings.
"We've got a bit of coin. We sold a house in Auckland."
Interrupted from their Friday morning cream doughnut and coffee habit, they told the Chronicle about their 10 years in a slum in Manila, the biggest city in the Philippines.
In 1985 they took their two children, aged 9 months and 2 years, to live there in "a basic abode of plywood and corrugated iron, with a mud floor". The children went to the local school and became fluent speakers of Tagalog. Their next baby only lived two weeks, due to "a bug" in those conditions.
Their aim was to make the people and the place better, but Mr Duncan said for the first five years they did it all wrong.
"We did things for people, but not with them, which created unhealthy levels of dependency."
After a stint at Oxford University they returned with a more empowering approach, involving the people in decisions.
None of their later projects failed, but after 10 years the slum was intentionally torched by a wealthy foreigner who wanted to clear out the squatters and build townhouses. No one was killed but the people scattered.
For the last years Mrs Duncan has been CEO of Iosis, a Christian social work provider for "broken people and broken families" in South Auckland. She has a nursing background and came to a relationship with Jesus in Christchurch as a teenager.
Mr Duncan's father Ian is a former Kai Iwi farmer. He was sent to St George's and Wanganui Collegiate schools and then expelled from Massey University for his hippie lifestyle and using and dealing LSD.
He fetched up in Christchurch where he would listen to the man who called himself The Wizard speak in Cathedral Square. Also speaking would be "a little old fellow with a big black bible". He got talking to one of the preacher's followers, a young man who asked him where he lived.
On finding he didn't have a place to stay the young man gave him his own rent-paid room and everything in it. Amazed by such generosity, Mr Duncan started reading the bible left by the bed, and found Jesus himself. He met his future wife at a Spreydon Baptist group.
Now settling themselves in Whanganui, with the luxury of organising a house the way they want it, the two are taking an interest in what goes on and waiting to see how they will get involved with this community.
