Martin:

"Just to confuse the issue further - where does the American snse (t-shirt?) of "skivvy" come in?"

It's a bit of a stretch, but how about a skivvy is a (domestic) underling, and a skivvy (vest, undershirt) is an underthing? The skivvy=vest is first recored in America about 1930, I think

There's a new edition of Patridge's Historical Slang out -- actually, it came out a year or so ago -- technically the 8th ed., which I have on order. I'm hoping that may give some more details. The +major+ revision of Patridge -- which will be the ninth edition -- in two volumes, isn't due out till 2005, alas.

Robin