Ended up having a look inside the cam cover as I had suspected it was blocked up, there seemed to be quite a sweat of oil down the front of the cam cover that warranted further investigation. The cam cover seemed to be welded on, after removing the 10mm cam cover bolts, I had to hammer a screwdriver through the gasket in various places to break the seal. After getting it off though it seemed there wasn't any problems with gummed up pipes or the little mesh thing in cam cover. It was just a bit dirty as you would expect. I was in a kind of couldn't be bothered doing any bodywork mood so decided to have a wee play with the engine.
Still good to give all the breather hoses and the mesh filter a good clean.
Sadly all my 8 valve Vauxhall engines have dribbled from the cam cover gaskets.
Usually within a matter of a few weeks of a thorough clean and fitting a new cork gasket.
Cav mk2 -13S
Cav mk3 - C18NZ
Cav mk3 - C20NE.