The younger lad Rory Reid does a good job of presenting the Extra Gear on-line programme that goes out straight after the main programme is aired. He's natural, likeable and hasn't got a 'me me me' attitude, however, I personally feel the BBC should have retired Top Gear and released a new motoring programme in its place, but then its all about the marketing factor of the name; kind of a 'tail wagging the dog' scenario.
If they need a replacement presenter, yeah I agree with Gary that Guy Martin could do the job, but as I mentioned earlier in the thread, Steve Sutcliffe who does on-line motoring reviews for Autocar, broadcast on YouTube, would be excellent. If you don't know him, just look up any of his car reviews on YT.