Found the *******rattle the pre tensioner on the Cambelt NTN Brand the piston could be pushed back easily by hand put the original back on NO more clack clack this had only covered 5000km along with new belt etc I know the pre tensioner has been covered for start up rattle but this one only came in at idle on a fully warmed up engine and sounded like a Lash adjuster.:facejump::hmm::woot::kb:

Isn't NTN one of the better brands? Any signs of fluid leaks?

Take it back and show whoever you paid good money to. (If it was sourced locally)