@Gloss yeah I don't agree with a thing you said. First off, even if there was an implied limit to the scenario (which I disagree with) the OP hasn't shot it down yet so it must not be too objectionable an idea. Second, if that's your definition of cheating then my follow up is "who cares/so what" (take your pick), it's an arbitrary label for said tactic at best IMO, and unless it hurts the intent of the OP (again correct me if I'm wrong
@Hvalrossen ) I see absolutely nothing wrong with it.
Finally, the notion I posted would've seen a different ethnogenesis between the Angles, the Salian Franks, and the Frankish-influenced Saxon "Jutes". In other words, not even OTL's Anglo-Saxons. As far as points brought up by
@The Professor then we're likely talking a split between North and South Gaul which wouldn't need that early a PoD, and a stronger Briton defence could help things along in that regard too.