I saw that this thread was coming up....so after virtually no digging around I have found this from the British Comedy Guide.....
Up to series H these are the most appearances
25 Jo Brand
24 Phill Jupitus and Sean Lock.
22 Bill Bailey and Rich Hall.
17 Jimmy Carr
14 Clive Anderson and David Mitchell.
13 Rob Brydon
11 Dara O'Briain
9 John Sessions
8 Jeremy Clarkson
6 Andy Hamilton
5 Danny Baker and Sandi Toksvig.
4 Ronni Ancona, Jack Dee, Jeremy Hardy, Vic Reeves and Johnny Vegas.
3 Ross Noble, Arthur Smith, Linda Smith and Mark Steel.
2 Gyles Brandreth, Hugh Dennis, Howard Goodall, Charlie Higson, Eddie Izzard, Phil Kay, Fred MacAulay, Lee Mack, Doon Mackichan, Rory McGrath, Graham Norton, Sue Perkins and Liza Tarbuck.