My car is in dealership - hopefully they will find out what the sound is.... Any ideas or anyone had similar??

Sounds like normal TSI engine HPFP and injector noise to me.

The engine seems quieter when clutch is pressed in. Its an intermittent issue only noticeable on idle.

Yeah when you press the clutch you disengage the gearbox shaft, that's what rattles a bit. Pretty normal though on most cars.

I'll see what they say.... Other than a bit of noise at idle, car is great.  Dealer has given me a Rapid Spaceback courtesy car.  I must admit I like the Octavia much more. It seems more grown up and smoother all round.  Rapid seems a bit bargain basement in comparison. 

Dealer is keeping car in for a week so it seems they have found something amiss.  Hopefully it will come back in once piece.

UPDATE:  Car is having a new clutch fitted. 

You still having this tapping sound with the new clutch fitted?