Am a complete mechanical numpty. What do you make of the following?

Vauxhall Signum 1.9 diesel, nearly 5 years old with 82k on the clock. Serviced on schedule (though not main dealer) recently had a new cam belt and water pump fitted by Halfords.

A couple of weeks ago I noticed a high pitched, metallic, whine coming from the engine bay. As whines go it's pretty quiet, other people can hear it, but only when I point it out to them.

It's most obvious in town when I'm doing 20 - 30mph and disappears completely whiIst the clutch pedal is depressed.

Am assuming it's the clutch, my experience of the Vauxhall is that components aren't built to last like the Subaru and Audi that preceded it.

Is it likely to be anything else?

Cheers