I recently changed the canbelt on my Xantia HDI after it jumped out a
couple of teeth when the tensioner failed. It is an interference
engine. However in my cas instead of bending the valves it broke 4 of
the rocker arms. Much less costly and time consuming to repair. If I
were you I would ask the garage to check them first before trying to
take the head off. Believe you me, there is hardly any room to work on
these engines, especially at the back where the manifold is etc.
Just ask garage to take off rocker cover as a preliminary check and get
a torch in there and check the rocker arms are in one piece.
As the valves operate in a vertical plane on these engines it is
unlikely that they will have bent
Hope this helps
Mike

It's a petrol, HPI 16v.