Interesting to read your early comments. I tested with Ancestry and discovered that my dad was not my genetic dad, much to my surprise, and that my ethnicity was largely Irish and Scottish (via the USA). Prior to that all my paper research carried out over 20 odd years had seemed to prove that both sides of my tree were solidly English back to at least the 18th century.
I have come round to the idea that my paternal tree is rubbish but I remain convinced that my mother was as English as they come. But Ancestry says that I have less than 5% of Northern European blood in me. Now, unless I was a foundling adopted by my apparent mother, it seems odd that the women who passed down 50% of my DNA should be ignored by the Ancestry ethnicity estimate. And yet the MH estimates are generally considered to be much cruder and likely to give you the weird results you found.
So don't bother too much with ethnicity. Concentrate on the DNA matches which are far more reliable.
