OMG!! I have finally solved the riddle that has been bugging me for about 6 weeks. You have no idea how releaved I am. It has been the weight of the world on my shoulders and has practically sent me into early dementia.
what was this riddle? well...
I'm not much of a TV watcher but my puter is in the living room and I sit with my back to the TV so I generally hear what's going on. ITV have been using a particular song as a trailer track. Well, I say song, it was a heavy guitar riff. I didn't know what it was and I heard it advertise several different TV programmes coming up, but also Top Gear used the track. It was driving me mental! I hunted the internet but with very little info, found it hard to use the right keywords. I couldn't find anything. Then I remembered that it had been used to advertise The Devil's Whore, so I searched again and voila!! I found out that the track is by Elbow and is called Grounds for Divorce. I heard the full song a while ago and really liked it, but didn't remember where the guitar riff came from.
I am so pleased I now know what it is. I've heard it advertise so much since... and I keep pointing at the telly saying.. I know what you are now... LOL
Here's the song in full... wait for the guitar riff in the middle and another towards the end.. you may even recognise it.