I like bacon and the full seafood selection too much.... and all the lesser-known things about keeping kashrut are daunting, too. (Like beef stroganoff? Meat in a cream sauce? And what's wrong with that great English dessert, trifle? Can't go wrong with trifle... errr... if animal-based gelatine went into the jelly as a setting agent, it's most likely to be pork-derived.... at least smoky bacon and prawn cocktail crisps are permitted, as these two flavours never went anywhere near a living pig or prawn at any point. But G-d help you if you want roast chicken, as the flavouring agent for this crisp flavour - yes, comes off a pig.)
As i say, I asked - would this make an objective diference to anybody except Heinrich Himmler were it to turn out to be true - and the answer is "no". The matrilinear thing is crucial, and anyway I don't feel "drawn" to Judaism.
But Britain is one of the best documented nations on earth for public and family records. If my family have got difficulties in conclusively proving the ethnicity of a great-grandparent one way or the other, a generation so relatively close to us in time - then imagine the USA in the 1800's.
You might get a young man with a romantic imaginative streak who's heard a family rumour that great grand-daddy was a Shoshone Indian, but "we don't like to noise that around too much as the one-drop rule applies", or else we think it's true, but there's no paperwork to prove it. And, well, maybe some of the fakers might not have been totally faking it after all. Which is like me noting that if 1/16 of my genetic identity comes from cCunty Dublin, or is it Carlow, or is it Kildare, and despite my never really having been there much above once or twice, posing as Irish... a tiny bit of fire and an awful ot of smoke.