Engine Cover Bolt

Hello everyone, I have a 2002 TD4.

I have gone and lost one of the bolts that hold the Engine Cover on, speficically the cover that goes over the injectors and not the one that covers that air filter/oil cap.

What size bolt do I need to order please? As I am getting a small amount of oil leaking from the hole.

I have searched the forum before asking.

Thanks

I have a feeling they are 10mm but do not take my word for it

They're M6 thread

Second that they're a m6 thread and 8mm head by 20 to 25mm long

sorry it is the old grey matter I was going of old memory as my newer 2006 model does not have the big engine cover

Thank you for all the replies chaps!