I can answer that now. A set of maps that demonstrates the geographic spread of my direct ancestry back seven generations, to the early 18th Century.
I used a cropped relief map of England from Wikimedia Commons. Attribution is: By Nilfanion [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons.
The red dots mark the locations of each ancestor, preferably a birth or baptism place, if not, then the next best provenance.
Great Grandparent Generation
Great Great Grandparent Generation
All sixteen ancestors of this generation are represented on this map. They are concentrated in Norfolk again, but with single representatives each in Suffolk, Cambridgeshire, London, and Oxfordshire. These ancestors were all born between 1830 and 1865 in England only. They represent four generations back from myself or my siblings.
Great Great Great Grandparent Generation
Thirty of the thirty two ancestors of this generation are represented on this map. The other two were undeclared fathers. The main cluster is still in Norfolk, with a particularly dense cluster in the east of the county, around the River Yare. Outside of East Anglia, I also had ancestors at this generation in Oxfordshire, London, and Lincolnshire. These ancestors were all born between 1794 and 1837 in England. They represent five generations back from myself or my siblings.
Great Great Great Great Grandparent Generation
The years and generations represented on the maps pretty much cover the past three hundred years of industrialisation and globalisation. Much earlier, I'd expect less movement. Therefore I feel that it would be safe to assume, that back to at least the medieval period, that my ancestry was concentrated in East Anglia, with a secondary patch in the Wessex area of England. The recent POBA (People of the British Isles) 2015 study, suggested that the old Anglo-Saxon kingdoms continued to act as localised gene pools into the high medieval period.
Before that, we had a period of immigration waves into lowland Britain. The POBI study, supported a number of other recent studies based on genetic profiling, archaeology, and place-name study, to suggest that Anglo-Saxon immigration accounted for no more than 30% to 40% of lowland British DNA, and that the majority of English heritage had existed in the British Isles previous - perhaps to influxes of genes during the Bronze Age or earlier. Genetic profiling of human remains in Cambridgeshire, of people identified as 5th Century immigrant (Anglo-Saxon), suggests the closest present day profile as Dutch or / and Danish. The kingdom of East Anglia identified with the Angles ethnicity, that historically provenance their origins to the region of Angeln, on the Danish and German borders on the Baltic coast. However how elites identify their origin, is often not based in fact, neither is their origin always shared by their subjects.
East Anglia fell to the Danish army, and subsequently to Danelaw control periodically during the late 9th to early 11th centuries. Some parts of East Norfolk such as Flegg, are particularly rich in Old Danish place-names. POBA 2015 failed to identify a Danish presence with their genetic profiling, but the place-name evidence and historical sources contradict this finding. The 7th to 9th centuries saw a slight reduction in sea levels, that enabled the draining of new lands in East Anglia for settlement. The same districts are rich in Old Danish place-names, strongly suggesting immigrant settlement.
POBI 2015 suggests that I have ancestors that have lived in lowland Britain, since at least the Bronze Age, and most likely, much earlier. That very likely ties me to lowland British ethnicities of the Bronze and Iron Ages. The dominant power in East Anglia during the Later Iron Age was the Iceni federation, famous for the Boudiccan revolt against Rome.
POBI 2015 and other studies, suggests an Anglo-Saxon immigration that accounts for 30% - 40% of English ancestry. My strongest cluster is concentrated in the river valleys of East Norfolk, exactly the sort of landscape that I would expect any North Sea immigrants during the 4th to 11th centuries to concentrate. Therefore, I would expect a high probability of actual Anglo-Saxon immigrant ancestry (based on recent studies, from the Netherlands area, and perhaps North Germany / Denmark). Based on place-name evidence the area was later heavily influenced by the Danish.
When I receive my 23andMe DNA results, based on their genetic profiling of Y chromosome, mtDNA, and on general autosomal calculators, in their ancestry results, I would expect to see overwhelming British & Irish percentage. However, will their autosome crunchers also predict a percentage in the Scandinavian, French & German, and North-West European 23andMe categories? As autosomal DNA is so random, what will the results display?
Still waiting for the results. 23andMe are not giving a very rapid service. For starters, I received a sample kit with a Netherlands return address. That apparently was a holding depot, where they stockpile some of the European samples, so that they can ship them to the USA cheaper. My sample reached a US lab, but continues to sit in a queue. It has now been 37 days since I sent my registered sample off, and the box is still in a queue, waiting to be tested. Other customers are reporting some long waits further down the process in quality control. I expect a long wait.