good to see you've only got 867 posts to go dom.
i thought about trying to do this myself, born in the uk, parents are from lithuania, and i thought of getting a lithuanian passport, and trying that, but seeing i've never been to lithuania, and how can you excerise your treaty rights in the country your born in . i was sure the gov wouldn't allow it. as i said before it states in the info, family permit doesn't normally apply to british citizens.. so i went with the spouse visa
but if people have done it, good for them, but will you have problems in 5years , hope not.