And there is the description I remember from my childhood of an unattractive woman (at least in the eyes of the beholder) - "she's as ugly as a hat full of arseholes".

My first husband, who came from a small town 100 miles north of my home town, used expressions I had never heard of such as "grinning like a goat chewing a quince", "grinning like a cat shitting razor blades" (very self explanatory!), so-and-so was said to be as slow as "an old gin (Aboriginal woman) handing out Bibles at a christening" - very non-PC these days. And something unusual was said to be "as rare as rocking horse poop".

I guess it is pretty rare.

Cheers
JennieG