The Votadini exodus to Wales

[romanonick]

Although outside the scope of the Roman occupation period of Britain, the Votadini (hitherto a buffer or client kingdom to the immediate north-east of Hadrian's Wall) appear to have 'saved' the people of 'Wales' from the Scots (or Irish raiders), migrated their indigenous military and domestic customs and formed the foundation of a kingdom which lasted until Llewellyn. A huge claim to fame!!!!!
Reverting to the tribal 'Gododdin' name - sub question - is 'Votadini' the latinised name for 'Gododdin' ? - this tribe, springing from the hinterland of the Wall, appear to have partly 'saved' the 'British' nation from complete foreign extinction - largely because of expertise learned from earlier Roman military equine practice. Cunedda is the name of the main man to conjure with here apparently along with Macsen and others.
I have read a very readable account by the author Alaistair Moffat (Arthur And The Lost Kingdoms) of these exploits and (although I'd love to believe them) I am struggling to bridge the credibility gap of the story (can one call it history?). All sorts of questions are thrown up - first and foremost - if the story is true WHO requested their help and WHY did they feel obliged to respond so positively ?
I should like to ask whether anyone out there has anything to add (for and against) this - on the surface anyway - wonky piece of bardmanship!!?? :? ? .