weird knocking

All,

Has anyone else noticed this: It's quite specific so bear with me while I explain!

Basically, when I come to a stop, and depress the clutch, I can sometimes hear a quite quiet knocking sound. The sound is coming from the front - sounds like it's behind the engine (towards me) but fairly low down. It also stops after a few knocks, as if something's been moved by the clutch and is bouncing back to rest. I've not totally pinpointed it - it could be the stopping of the car that's doing it (which would make sense if say a hose was loose or something) - but I've got a hunch that it's the pressing of the clutch that's doing it. I don't generally hear it in normal driving, only really when I stop outside my house. It's on a hill and it's most pronounced when the car's pointing downwards.

So, does this ring any bells? Anything I can easily check? I couldn't see and loose hoses etc. when I had a quick look before - despite much manly waggling under the bonnet! Anyone else experienced this spookiness?

Russ.