There are quite a few of us doing it - pop over to the Forums Cafe and look for the "Grade 6 Theory Challenge" thread. Forum candidates include me

, AnotherPianist, YetAnotherPianist, bohemian, mrbouffant and jm-hamilton; I think I've seen that deviless and a couple of others are sitting it as well.
I haven't done any exams at all since 1994, and the last theory exam I did was in 1987, so it's not just figured bass I'm having to revise. As long as I pass I'll be happy, and any marks above the pass mark will be a bonus!