Last week the car decided to chew up its water pump, local dealer replaced it under warrenty along with the timing belt. Just recently noticed I'm now getting really poor mpg. Used to get about 44mpg now getting around the 38 mpg mark.
Is there something they could of done to cause this??

Also had to tighten up the 2 engine mount bolts 2 days after picking car up so it wouldn't surprise me if they had missed something.

The car is a 08 plate 1.9 cdti 150 if that makes a difference