When we've been in London on a Sunday evening these last few years, we go to the Lamb & Flag on James St. (near Covent garden); it's a great 17th C. pub (Pepys, Johnson, et al drank there; they appear to have done little else!), but on Sundays for the last X number of years they've had the most terrific Dixieland jazz band--a real jam session, and the woman who sings w/them is called Mary (I think her last name is)Robertson. ANYWAY, we heard her sing a great version of "Salty Dog" last time we were there; there appear to be many variations on the theme!

Sorry to digress, but if you're ever around on a Sunday night, definitely check them out!