Charlie, it's not just a down under thing. I have had the same problem especially on one of my guitars. I got some help from Todd (Fitness1) on this board about this problem which tends to be due to the saddle. He gave me some advice on compensating the saddle, which is basically to remove some of the material on the front side of the saddle beneath the B string. I did it with a semi round file at about a 45* angle. Here's a picture of mine. This has helped my B string intonate better. Edit: I also forgot to mention as others have said below that using sweetened tunings helps a great deal.
