Non-Brythonic admixture in Britannia

What is most interesting concerning the subject of Germanic admixture in Scotland is the fact it is the east/north-east that is seemingly the most Germanic, or at the very least, just as 'Germanic' as the south-east. I will always be very appreciative of Croeda hitting me up with the link to this;
https://i.postimg.cc/3NqVmk3b/Screen...1-24-33-AM.png

We lack information on SE Scotland, but one could assume it is genetically equidistant between the north-east of England and the 'Northern Irish' sample; I think we can be under no illusion the 'Northern Irish' segment refers to the Scottish-descended population within Ulster (and the vast majority of the Presbyterian settlers that came over from the 16th Century onwards were from the SW of Scotland). At face value, when we take into account place names, it appears that Anglo-Saxon settlement to what is now SE Scotland was negligible; even in the Scottish Borders the majority are of Gaelic or Brythonic origin. However, archeological research extracted evidence of some form of Anglo-Saxon settlement in said area, or at the very least in the village of Aberlady (Brythonic/Brittonic name), East Lothian. There is evidence of a large Anglo-Saxon structure in Aberlady combined with the fact that within the confines of said village an openwork pin head of Mercian style was discovered (through the same archeological research). This article (https://aberladyanglesdotcom.wordpre...axon-aberlady/) mentions how the pin head dates back to the 8th Century, a time when metalwork was 'rare' across England. This example 'far north of the usual geographical range' for this type of artifact emphasizes there was an Anglo-Saxon community of decent proportions in said area. But East Lothian is reasonably fertile when it comes to its landscape; you immediately head west and you are in Scotland's rather unpalatable Southern Uplands. Aberlady might have been quite an 'exception' as well, as it would have been an important port at the time for Northumbria's northern extremities.

Concerning the rather mindblowing 2022 admixture study that brought light to the substantial 'Iron Age French' component of the English genome, one does wonder how NE England is as Brythonic as Cornwall is, considering the phenotypical preponderance of Anglo-Saxon types from there, as well as the fact that only the northern part of Northumberland has a decent proportion of Brittonic place names (along the south and east coast you basically just see Anglo-Saxon names). Could one argue that certain aspects of the study aren't quite as valid as they seem? For example, Cornwall is practically devoid of non-Brittonic place names, but yet South Pembrokeshire is genetically 1.5% more Brittonic, even though said area was (apparently) heavily settled by the English; the area has very few Brythonic place names. South Pembrokeshire (as well as Gower) was the ONLY area in Wales, from an historic context (pre-1800), to have some form of English settlement and yet to say the genetic difference between it and 'North Pembrokeshire' is negligible would be understating things. In fairness, Wales is a largely mountainous country, a country that was geographically inhospitable and unpalatable to the Anglo-Saxons. Cornwall, on the other hand, simply has the River Tamar as its geographic bulwark, although the genetic difference between it and (central) Devon is seismic compared to the difference between south/north Pembrokeshire. It can be compared to the difference between Gloucestershire/Forest of Dean.

The crux of my issue concerns Cornwall, NE Scotland and South Pembrokeshire. In the context of the latter, the Royal Burghs of Scotland enticed many merchants from England and it appears the areas that were beset with the greatest influxes were Fife and Angus, but Banff/Buchan is still in that same trajectory, I didn't think something of this nature would concern rural populations too, but the admixture is too great to seemingly just be confined to the big towns. Either that, or it is a 'blip'. We also read about the English nobles who fled up north after the Norman Conquest. I found an article from a Scottish man concerning the origins of his surname, 'Wighton' (https://wightonfamily.ca/genealogy/e...lo.norman.html) and how his paternal line originated in either Yorkshire or East Anglia before his ancestors eventually migrated up north; his earliest patrilineal ancestor was traced back to Dundee in the mid-15th Century. Dundee, ofc, is the epicentre of Scotland's east. There is a possibility that SE Scotland is just as 'Germanic' as Banff/Buchan. But the main tidbit is how there isn't always a direct correlation between settlement of people and the linguistic makeup of the area.