Just to back someones argument for a change DMcG, here's a quote from the BBC that supports the idea that language and ethnicity defies simple categorisation. This comment was made in reference to the BBC program The Blood of the Vikings"Surprisingly, mainland Scotland had a similar Celtic input as the population of southern England, showing that not only were the English never "homogenous Anglo-Saxons", but neither were the Scots predominantly Celtic."
But what the study showed was that Northern England (and Southern Scotland) was significantly Angle-ish