Comedy writers/performers who are only famous for their radio (and maybe publishing) work. Not counting the people in the "far past" where radio was a bigger medium-you know what I mean I'm sure...
Simon Brett
Sue Limb
Chris Emmett
Nigel Rees
Linda Smith (Not sure? Did do a bit of telly)
Chris Neill
Any more?
Ooh I dunno about Simon Brett. After Henry ran very successfully on television.
Maybe, not a TV presenter though.
Ah, well, presenting is a different matter. You didn't specify that! Granted. 
Boothby Graffoe?
Patrick Barlow has done lots and lots of excellent radio work
John Finnemore must be up there?
Quote: Will Cam @ 26th June 2014, 11:11 PM BSTJohn Finnemore must be up there?
First name that occurred to me.
Did Kenneth Horne ever do any TV?
Quote: lofthouse @ 26th June 2014, 10:21 PM BSTBoothby Graffoe?
A regular on a sketch/stand-up show, whose name escapes me, years ago IIRC.
Tom Wrigglesworth done any tele?
Quote: fasty @ 27th June 2014, 8:13 PM BSTTom Wrigglesworth done any tele?
I Googled him because I had similar thoughts. He has had some TV stuff but he is definetly better known for his radio work (he is a very funny guy and can heartily reccomended Tom Wigglesworth's Open Letters currently being replayed on iPlayer Radio).