Because I live in Brittany in the canton of Huelgoat, Uhelgoat in Breton, and on some old maps as Huelgoit, I thought that some people might be interested that the historical pre-Roman invasion British/welsh name for Exeter was according to some annales Kaer PenHuelgoit.

History.—Exeter was a town of the ancient Britons long before the Roman invasion; and it has made a conspicuous figure in every subsequent age. It was called by the Britons Caer-Isc, "the city of the water, " from its situation on the Exe, -anciently Isc, signifying "water;" and Caer-Rydh, "the red city, " from the colour of the soil around it. It was called, by the Romans, Isca et Legio Secunda Augusta, from its having been occupied by the Augustan legion; and Isca Damnonioum, from its having belonged to the British Damnonii, and to distinguish it from Isca, afterwards Usk, in Monmouthshire. It was called, by the Saxons, Exan-Cestre or Exacestre, signifying "the castellated city of the Exe;" and that name passed, in course of time, through the forms of Exceaster, Excester, and Exceter, into the modern form Exeter. It is called, by Geoffrey of Monmouth, Caer-Penhuelgoit, signifying "the prosperous chief city in the wood;" and by the writer of an old, local, legal document, Pennehaltecaire, signifying "the chief town upon the hill." It likewise bore, for some time, the descriptive name of Monkton, from the existence in it of many monasteries; and was described, by Henry of Huntingdon, as "Excestria clara metallis"- Exeter famous for metals-probably from its vicinity to the Dartmoor mines. It was the chief city of the Damnonii; it must, from the evidence of relics, have been an important station of the Romans; and it has ranked, in later times, as the capital of the south-west of England. Ancient roads went from it to Totnes, Stratton, Molland, and Collumpton; traces of camps are discernible in its vicinity; and many Roman coins, small bronze statues, tesselated pavements, fragments of columns, and other relics, have been found within and near its site.