You see the exact size of all the reference groups on Ancestry.
Most European ones are 2000.
Cornwall is one of the new regions added in the last update.
Whilst some of the marketing waffle is just that - blurb to sell more kits,it isn't all total rubbish.
If you go onto Ancestry and read how the assignment of regions is done (written by the science people not the marketing ones) it makes much more sense. What that also does is tell you what it really means.
My regions for example are (circa Jul 2024)
85% Scotland, 10% Ireland, 2% Iceland, 2% France and 1% Norway.
What that actually means is that 85% of the DNA segments Ancestry uses to define ancestral origins is more common in the Scottish Reference panel than any other. 10% is most common in the Irish panel than any other regional panel, and so on.
The 2% Iceland is new (as it is for everyone, it was only added with this update). Because it is new, the Iceland Reference panel isn't as large as most of the others, so a small group with similar DNA can have a disproprtionate effect on the results. So what does my 2% Iceland really mean?
It doesn't mean I "2% Icelandic." It doesn't even mean that segment is more common in Iceland than elsewhere. It just means that a small part of my DNA is more common in the reference panel for Iceland than anywhere else. That's all.