If you can download the show(s), you don't need a separate recording utility. Downloading seems to be possible with Zoomer Radio, despite the comment I saw somewhere there that the show is only available as a stream.
Using Safari, I started the flash track of the show immediately below Denis Snowdon's picture. If you then open Safari's Activity window (Window menu), you'll find there* a rather large mp3 file (about 90-100MB for an hour's show), easily the largest file in the page's listing of component files. To download that mp3, Option-double-click that line. Once downloaded you'd need an editor (like Audacity) to trim away those parts of an individual show you don't want.
*) When you do this you may want to limit the number of tabs open in Safari; that makes finding your Zoomer Radio page listing a bit easier.
