Cold start problems on a 2004 Vauxhall Combo 1.7 DTI?

I have a cold start problem on my 2004 Vauxhall combo 1.7 DTI van. I need to crank and pump it to get it started. Once running it seems ok but sometimes it will miss fire (like petrols engines do when there's dirt in the fuel line) then for no reason it will run fine again. mostly its a good runner once its warmed up.
Any advice on what I can check before I have to fork out an arm and a leg for an ECU.