Dear jmh: Your URL sounds as though some very distant sassenach cousin of mine has haggis for a first name. I wonder how that could come to pass. If I may be Caledonian enough to save space and energy, I just encountered in New Scientist a UK slang expression I cannot understand. In an article promoting genetically modified cats that would not provoke allergic reactions in the owner, there is a picture of a girl and cat cheek-to-cheek, and caption "ONE-OFF: all the genetically engineered cats will be spayed or neutered before they are sold."

Please tell me, what does the "ONE-OFF" mean?