DOES GEOFFREY OF MONMOUTH TELL US WHERE UTHER/GORLOIS COMES FROM?

[So far as I can tell, this is the last unpublished piece in my files.  Once again, I did not pursue the idea introduced here because I could not find a way to connect it to Arthur.  Maybe someone else can?]

Cornovii Tribal Territory

It has occurred to me that in taking another look at Uther Pendragon's Mount Damen, we might learn more about Uther himself.  For my work on identifying this battle site, please see the following link:

https://mistshadows.blogspot.com/2019/10/the-discovery-of-uther-pendragons-mount.html

In that piece I had asked why Gorlois, Duke of Cornwall, was first introduced at that particular juncture in Geoffrey of Monmouth's HISTORY OF THE KINGS OF BRITAIN.  My answer initially was because Gorlois (from Welsh gorlassar, 'very blue', used as an epithet for Uther himself in his elegy poem) might have been fancifully linked to the Blue Hills at The Roaches.  But might there be another, better reason why Gorlois makes his debut at Mount Damen?

As it happens, this battle is within the Roman period tribal territory of the Cornovii.  

[From https://books.google.com/books?id=gthTGHWl4LUC&pg=PA210&lpg=PA210&dq=%22barry+cunliffe%22%2B%22cornovii%22&source=bl&ots=TXGH8QGXyD&sig=ACfU3U2zp_UdbWaiYtTfDW5IblNR_tuCkQ&hl=en&sa=X&ved=2ahUKEwiZ-d6qxqrpAhUEpp4KHbyMA-UQ6AEwCnoECAoQAQ#v=onepage&q=%22barry%20cunliffe%22%2B%22cornovii%22&f=false]

The Cornovii bear a name which can be compared to the Cernyw used by the Welsh for Cornwall.  Could it be, I wonder, that Gorlois, i.e. Uther himself, the 'Duke of Cornwall', originally belonged not to the Cornwall of SE England, but here in what later became the nucleus of the Dark Age kingdom of Powys?