Rough Tick Over when Clutch Pedal Up

I used "Edge" as there is not a Transit label.

The Transit will tick over erratically rough if I let the Clutch Pedal up and not pressed with some clatter noise occasionally. If when I hear it clatter I floor the Clutch the noise goes immediately and does not return as long as I have the Clutch floored - the engine will tick over smoothly with the Clutch floored.

The Fuel Filter has just been changed and the Air Filter blown out.

There is no noise or roughness when driving normally.

Is this a Clutch Disc, Pressure Plate or Flywheel problem.