Thanks guys, i'll give it more time next time
Paul, I'm going to get my 350D modded in the future. That's why I got the 20D so I can keep that for terrestrial and mod the 350D, since I already have all the connections, cables etc to run it for astro.
It's going to be a few months before I can afford it though, but my imaging opportunities are limited by time (and weather) at the moment so i'm not in any great rush.