Ford FSD 2500: What Do You Think Is Wrong ?

[Simes]

I have a Ford FSD 2500 (Ford Transit Engine) One of Ford Europes Industrial units. Only done 300 hours, done 20 since I had a new Timing belt fitted.
Whilst at idle it stopped all of its own accord. It restarted and idled for a couple of minutes before making a loud "Clattering" sound from the front of the engine and then stopping again.

I have checked all of the obvious items like fuel (quality and quantity), fuel stop solenoid, the engine is not seized.

My only though at present is that the Timing Belt Tensioner has failed, I did not check with the Diesel Engineer at the time about replacing the tensioner as well.

Does anybody have any other ideas about what the issue could be, or about what checks I can make other than an inspection of the timing belt and tensioner (scheduled for this evening).

Many thanks

Simes