Hi,
I can tell you that there are 2 problems with the xml for the podcasts. The first is that the date on the feed never gets changed, the other is that the filename never changes. Most podcast/rss software applications use these two things to determine whether a new episode is available.
With that said, I've thrown together my own feed which tries to make up for that. it's here:
http://feeds.feedburner.com/MoonGriffonIt basically assumes that a new episode is available every day and puts up a new episode. It definitely isn't perfect and sometimes results in the same episode twice. I also work in a place where streaming is discouraged, so this helps me out with keeping up with the show, but I'm pretty sure I'm normally at least a week behind.
Again, this feed doesn't copy the actual show, just links to the files to download from moongriffon.com so if they aren't updated by about 10pm that night, it'll probably download an old version. If you'd like any help on getting a more correct podcast working, please let me know.