I agree a lot with Guy. The difficulty with ethnicity estimates is twofold.
(1) They are very approximate. Every company gives different results, often because they define their areas differently.
(2) They show, as Guy said, where you came from, but it isn't clear exactly how recently. You could have traced your ancestry in UK back to the 14th century within UK, but before that you might have Celtic, Roman, AngloSaxon, Viking, Norman, French, Spanish, etc, background, and earlier on, some Middle Eastern, Balkan or even Neanderthal.
It can be fun finding out all that, but it is unlikely to assist much with finding ancestors, and shouldn't disturb you to doubt your paper research.