[wilf leek]

Paul - it might just be rattle from the gearbox itself - try pushing your tickover up a tad to smooth it out and see what happens.

One way to determine if it is your throwout bearing is easy - if the noise stops as soon as you put light pressure on the clutch pedal (but not enough to disengage the clutch), it is coming from the throwout bearing. If the noise keeps on until you have completely disengaged the clutch ( and therefore there is no drive to the 'box), then it is from the box itself, and may not necessarily indicate a problem.