2012 focus tdci econetic...odd engine noise

[mx5cl]

Hi all

I've got an odd noise with my 1.6 tdci.

when fully warm at between 1,500 - 1,750 rpm under no throttle or clutch i'm getting a high pitch ticking sound not dissimilar to a bicycle freewheel! (before you ask there isnt anything in the tyres!!)

its back with the dealer for a second time for diagnosis, has anyone here encountered anything similar?

Thanks