Are ther any common or major problems with the 1.6 diesel engine that I should be aware of 

I read injectors and egr were common but not sure if the injectors are mainly on the earlier ones. Previous owner of my car had the egr replaced twice though withon a 150,000 miles. I got it turned down a bit when I got the car. Other than that it's a fairly strong engine. Darkside got one to over 250bhp before it developed any issues.

I've been lucky with mine. Pretty bulletproof. The  water pump driven by the cambelt can cause problems, that's all I can think of.