The problem seems to be that Countdown was filmed in Leeds (now Manchester) and travelling takes its toll after a while. It was fine for the original presenter, of course, as he lived in Giggleswick.
As Wogan lives in Taplow, this seems an unlikely thing for him to want to do at this stage of his career...
might be a nice number for one of the I'm an ex sportsman celebrity chef/dancer/whatever coloured dreamcoat to the sound of music bods... Could see someone like Anton Du Beke having a go... or Matt Dawson