Apart from a very pale skin tone, which burns in the sun, I don't really have any claims to an exotic ethnic background. I used to claim celtic herritage, but discovered one of my ancestors was a Spainard, apparently ship wreaked after the Spannish armada fled England and sought refuge in Scotland.
Here in the UK, official forms frequently ask this question, offering a number of complicated answers, offering options to describe country, region, even religion but all with some emphasis on skin colour.
My wife prefers Black British. Which is a bit strange because her skin is definately not black. More a radient brown like the sun set on a warm autum evening in an unspoilt wood.