Interesting to read that at one point they approached Jim Henson about puppet-building. He may have turned it down, but quite a few of the TMS studio crew ended up working on the show (set designers, directors etc), and don't forget that Louise Gold was the show's original Leading Puppeteer.
There was a very interesting even at the NFT on London's South Bank just before Christmas, about the programme, involving a panel of four "movers and shakers behind the show", namely: producer John Lloyd, voice-artiste Steve Nallon, Co-creator/Puppet-builder Peter Fluck, and, puppeteer Louise Gold.
For a slightly fuller listing of puppeteers, voice-artistes, and, writers involved with the show, you might find the following fan page of some use:
http://www.qsulis.demon.co.uk/Website_Louise_Gold/Spitting_Image.htm