Geoff, I just got a Burton seat from British/Burton Bike Bits over on your side of the pond (
http://www.burtonbikebits.net/seats.htm - scroll to the bottom), and I can't believe how comfortable it is, and how much an improvement it is over the stock seat.
Mine is more of a cafe-racer style (#DS001), but they've got several models to choose from, and if the rest are anything like this one, you can't go wrong.
I've got to add here that their customer service is A-1 as well.