Thanks! I've been worrying about the creak for a while. I thought bottom bracket at first but now I'm sure it's the saddle/seatpost (although after thousands of commuter miles, the bottom bracket deserves to be replaced).

I'll start with your routine and work my way down to the seatpost if necessary - though I don't have any idea what to do for the thudbuster if that's also a source of creaking. Poor old girl needs a total makeover (except for the Brooks, which is a thing of beauty!)