I have this week updated my 2013 piece “on the antiquity of the church of Glastonbury Abbey”,https://kingarthursomerset.wordpress.com/2013/07/17/on-the-antiquity-of-the-church-of-glastonbury-abbey/ after finding that at other Celtic Christian abbeys of the fourth to sixth centuries in Gaul, Ireland, and western Britain, the church and the founder’s cell were the first structures to be built, and the founder was invariably remembered and highly honoured in much the same way as Glastonbury remembered and highly honoured St. Patrick as its founder. Examples include, in approximate date order, Legugé and Marmoutiers (St. Martin), Whithorn (St. Ninian), Kildare (St. Bride), Bangor Fawr (St. Deiniol), and of course St. David’s (St. David).
I also took a fresh look at what William of Malmesbury wrote about St. Patrick at Glastonbury in his History of the Kings of England. So I’ve changed and extended the St. Patrick section of that post. The estmated date for St. Patrick’s building of the Old Church (the vetusta ecclesia) and with it founding of the Abbey is c450CE.
I’ve also expanded the section on St. Pol de Leon, and narrowed the indicative date range for his improvements to the Old Church at Glastonbury (the vetusta ecclesia) to 520CE, plus or minus at the outside 15 years. This takes better account of what the church dedicated to him at Staverton, Devon, says about itself, and the indications I could glean about when he lived and worked in Brittany.
kingarthursomerset 
I have just completed reading all your blog posts on this theory of Arthur and I am greatly impressed. There are several points where I differ in interpretation but this is by far the most cogent construction of the fifth – sixth century divide I have read in years.
Thank you for sharing this interpretation.
Do you have a book in the works or does the blog entail the totality of the subject matter?
Also, if I should use any of this data in another context, to whom should I credit it?
Thank you for your expression of support and your kind words, R S Marshal. One advantage of my construct is that it is consistent with the evidence that seems to have early roots, albeit it goes beyond the evidence base. I am curious about your “different interpretation”.
Alas, I have not had time to focus on this lifelong interest of mine more than occasionally in recent years and, sorry, no, I don’t have a book in process. If you wish to quote me, my name is Wade Miller-Knight and a link to the relevant page of this blog would be good.