The journey out of London is accompanied by a radio debate about the north and south of England.
A London caller who says no one in their right mind would want to live in the north gets a gloves-off reply from Yorkshire. No sane person would live in London. And so on down the highway until the sign to The North appears in dominant letters above the motorway. It feels as if we are crossing the Rubicon.
At least you will discover that London is not England, I promise my London-dwelling son Tim who has decided to accompany me north on a journey to find the places where our forebears lived.
He navigates us off the roundabout with a road map that includes London's restricted traffic zones. Five seconds inside one of these is enough to incur a $20 fee.
Our ancestor search is helped by my father's memoirs which pinpoint the three places we will visit - one in Lincolnshire and two in Lancashire. It saves us the need to search official records, although the internet makes the job much easier these days.
Childhood memories of being intrigued with stories about forebears grow stronger on the approach to Lincolnshire. Back then I had tried to imagine the countries my ancestors came from. And the wrench of parting from home for unknown futures in a country on the other side of the world.
I was told about circumstances in Britain at the time which made life seem more hopeful in a young and uncrowded country like New Zealand. Even so, I sensed the courage of such a move.
And now we were leaving the motorway and following country roads which narrow to the width of a car. A patchwork of ploughed fields spread over the plains of Lincolnshire, and under arching trees we find the village of Swaton where my great, great grandfather, James Allen, had taught at the local school.
Sturdy brick houses with pitched tile roofs lie either side of a lovely old church. In the graveyard, weatherbeaten headstones keep silent vigil.
Down the road, the schoolhouse where James taught in the early 1800s has been converted to a private residence but the view is still of open fields. According to a long-time Swaton resident we meet, the village has changed little since that time.
But what would James, who went on to head a grammar school, have made of today's use of calculators in maths exams? And the drift away from the study of Latin and Greek?
In the church we slide into a pew and the silence fills with thoughts of family attending services there more than 150 years ago, and of their horse-drawn expeditions to nearby Peterborough, an important town in the area. And of James' son Vincent Allen, who was born in Swaton in 1850 and struck out for New Zealand in his early twenties.
In Kaitangata near Balclutha he applied his accountant skills for a coal mining company before moving north to Auckland. These family forebears feel within reach and both Tim and I are moved by the experience. It's hard to leave the peaceful village of Swaton when the time comes.
From the flat expanse of Lincolnshire we drive north towards Lancashire and the folding Pennine hills. Wooded valleys open to brooding moors. Towns give way to pint-sized villages. National park encompasses large tracts of the Pennines and, absorbed by the scenery, we almost drive past Holcombe, the birthplace of maternal forebears.
The 16th century former inn called Higher House where my mother's side of the family had lived from about the 1860s was built on the edge of the moor by an old coaching road. Opposite, and with a fine view of the valley below, is Holcombe church which had been built under the supervision of her great, great grandfather. Apart from a sprinkling of small dwellings the only other prominent building in the rural pin dot of Holcombe was an old pub, The Shoulder of Mutton.
After identifying family graves in the churchyard we turn our attention to Higher House. I glimpse someone through a window and experience an irrational wave of indignation. How dare strangers occupy the former home of my forebears? Reason returns when the front door opens. "Can I help you?", asks the current owner. We explain our reason for lurking outside, he is intrigued and invites us in.
It is fascinating to be inside the home that, 150 years ago, had resounded to the clatter of the large family into which my grandfather, Frederick Thorp, had been born.
The old stone house has weathered 400 years so far and my mother would have been glad to see the way the current owner has preserved and tastefully furnished it. As a student in England in the 1930s she had written to family in New Zealand about her own visit there and how she had climbed up the wild moors behind to a memorial to former British Prime Minister Robert Peel who came from the area. I notice the austere monument rising from the ridge and guess the view from up there would be its saving grace.
We leave Higher House with an invitation to return and the continuity feels comforting. Before leaving Holcombe the two of us puff up the hill that would have been my grandfather's playground. Grandpa Thorp had followed an older brother to New Zealand and, not yet 18, had set up a flax mill in Foxton employing 40 men.
After a fire ended the enterprise he joined his brother in Hawkes Bay to establish a footwear business which was to continue for another 85 years.
To reach our most northern ancestor destination of Lancaster, we set off through the scenic Forest of Bowland. In neighbouring Yorkshire they tell you the Yorkists won the 15th century War of the Roses between the Houses of Lancaster and York. In Lancashire they remind you that the decisive battle which took place on Bosworth Field in 1485 was won by a Lancastrian army raised by Henry Tudor against Richard III.
It was basically a family squabble but you need a large coffee and a jar of aspirin to get through it all, quips the concierge when we check in to the hotel in Lancaster.
These days when there's talk about the Wars of the Roses it's more likely to be referring to sports rivalry between Lancashire and Yorkshire teams.
The historic city of Lancaster was home to my father's paternal forebears. Lancaster Castle dominates from its hilltop position as it has done for the past 900 years and serves as law courts, prison and erstwhile theatre. Tours of the castle invariably tell of the 1612 trial of the notorious Pendle Witches. The last execution took place at the castle in 1910. Nowadays it is a major tourist attraction.
Fine Georgian buildings on Castle Hill date from the time when Lancaster's merchants were riding high on the slave trade and money was pouring though its quays and counting houses. The Maritime Museum on the banks of the Lune River is a poignant reminder of changing fortunes when the slave trade was abolished and the Lune gradually succumbed to silt. Nowadays people worry about the decline in fish species that used to fill the waters of nearby Morecambe Bay.
Lancaster climbs from the Lune to the centre of town where our ancestors James and Emma Woodhouse lived in their home above their wool and linen shop in busy Market St. The sight of a sportswear sign now hanging above the shop feels like a slap in the face. Music bangs out from the racks of denim and polar fleeces where, 160 years ago, customers had quietly contemplated hand- embroidered garments.
It is not the first time on this journey that I grapple with the insensitivity of changing times. There is some consolation in finding that the upper floor facade of James and Emma's former home still looks like the one in the photos we found in the Lancaster library archives.
Because James' older sister and her husband were prospering in New Zealand in the 1870s he decided a few years later to move there with Emma and their four children - one of whom was my grandfather, Arthur Woodhouse.
Buttoned up against the crisp autumn, Tim and I imagine them closing their shop for the last time - their final glimpse of Morecambe Bay as they left for an uncertain future faraway.
We feel close to them here, where they said farewell to England. Very close. They may have stood where we now stand, and I pick up a fallen leaf and slip it into my pocket. For old time's sake.
Resources to help delve into the past
* The internet is an efficient source of ancestor information. Useful websites for the United Kingdom and Ireland include familyrecords.gov.uk and ukcensusonline.com, while scotlandspeople.gov.uk is where you can search for Scottish genealogical data. A good site for New Zealanders to find out about their Irish ancestry is gogreenireland.co.nz.
* The Mormon church has compiled family records from around the world on familysearch.com.
* In London, the services formerly offered at the Family Records Centre relating to census returns, wills and other sources are now available at The National Archives in Kew.
* For the services relating to births, marriages, deaths, adoptions and civil partnerships see gro.gov.uk.
* Register House in Edinburgh is the place to look for Scottish ancestors.
* Libraries are good sources of information. Some have genealogy sections.