This is killing me and I really hope somebody out there can help.

There's a (very short) guitar riff that played between 27:51 and 28:08 on the latest episode (easily "findable" on iPlayer)... I know that I've heard it before, but I just can't place it.

Please can someone put me out of my misery ...

A clip with just the guitar riff is available to see here:
http://www.youtube.com/watch?v=4KTqWmN-BNg

I really hope this is familiar to somebody ...

Have just listened to it but don't recognise it I'm afraid.

snow patrol - somewhere a clock is ticking

Thank you! Thank you! It was killing me!!! You've spared me all that suffering! Thanks

On a side note OP, you've made 9 posts in 5 years ?!

What can I say? I'm a bit of a "lurker"!

By pointing that out, you've made me notice that my receiving equipment list is about 5 years out of date! I'm not using that Philips rubbish any more! Have to change that ...