It is correct that some of the HDi engines run high-mileage/lon-life cambelts, and 144k is something I have heard of many times, but id still be looking to get it done pre-100k if I were you, certainly something to consider.
Also, get the tensioners and water-pump done at the same time, its not much more cost for the parts.
Diesel cambelts don't tend to suffer the same amount of strain/wear as petrol, because they are lower-revving, but the general rulle is, whatever the service schedule says, half it or thereabouts, to be on the safe side. If the belt breaks, the cost of a repair to the engine is prohibitive to the point you may need/be cheaper to source a new engine, so for the sake of the cambelt change cost, its worth keeping on top of it.