It's been on my to-do list since Rakaz published his guide to moving from Atom 0.3 to Atom 1.0, but now I've modified the Mooquackwhatnotbot to produce an Atom 1.0 feed.
Doing so was virtually painless. The only problem I had was ensuring that entries without any descriptive blurb got some nominal summary text; but that was my fault for repeating the same code in two places and only remembering to change one instance.
As of the next entry, the main Atom feed will be in Atom 1.0 format. For those who're using a feed reader that only supports 0.3, I'll keep an up-to-date Atom 0.3 feed online at http://gkn.me.uk/atom-0.3.xml for a while, but I will stop updating it pretty soon (probably when Thunderbird 1.5 Beta comes out).