I believe there is evidence (geneologies, I think) for a 5th century Coel (Coelestius ?) in the norhtern part of sub-Roman Britain, though I don't know of anything linking this Coel to the town of Camalodunum. Why did the English invaders renamed the city of Camalodunum after him, calling it "Colcester" ? I don't think anyone knows. T.