I have had my timing belt replaced last week at a cost of £260, this included the 2 tensioners too.....
Sorry to sound like a real cynic, but do you trust this mechanic and do you know for sure that the belt was really replaced? £260 seems very cheap. I know the kit is about £80 or so..
What engine do you have? And what Espace?
With regards to the water pump; just keep going and keep an eye on your water temp.