I just took off the front breather hose to the breather pipe that goes to the sump and I was unpleasantly greeted with a Mayonnaise type substance.
The breather pipe has only been on there for a few days as I've recently had it changed so what you see is about 4 - 5 days worth.
I've checked the oil filler cap and had a look down where the filler cap is and that looks okay. The header tank looks fine and clear and the breather going to the cross over is fine so it's only the front breather that has this residue.
New head gasket time?