R1B is not typical Brit at all it is Typical western europe. The present royal family are R1B has was the last Russian Tsar and the last German royalty. SO please get facts right.
Guy Angles Saxons and Jutes are German therefore would fall into your English German lines
Lindsay DNA testing and results is based on probabilities and therefore not 100% Therefore some supposition is indeed used.
K Garrad Guy is technically correct. The division of English Welsh and Scottish is fairly modern. The Welsh are in fact Celts and have French blood. The Scots or should that be Gaels have Viking blood and thus are descendents of the North Germanic people and we English are a mis match of German French Italian and other European countries. So Guy was actually stating what couldnt be seen and you have failed to see this.
Devon A-DNA at 5 generations has I believe only a 10% accuracy and therefore not worth anything.
Now on to a pet hate of mine the US and genealogy. Some Americans are happy to accept anything they are told. As an example there is a book available on Wyatt genealogy in the US that has a relationship and children from the said relationship which could not have taken place when the Wyatt male actually died at 13 with no children of his own. Try telling the US Wyatt descendents this and they will call you an ass because it is written down. Therefore they are being told by DNA companies that XYZ is how it is and they accept it without question. One US researcher told me in an email only yesterday on this subject that she uses DNA becuase she cant afford to come to the UK and carry out a paper trail research project. Now she couldnt understand that without the paper trail she couldnt say with any certainty that what the DNA was showing her was in fact correct
Rob