Oil in my spark plug wells?

[Patrick_g46]

I just changed my plugs and leads to try and solve a misifirng problem and there was quite alot fo oil in my spark plug wells? Whats the deal with this? Rocker gasket?

Could this have been whats causing the misifirng below 2.5k revs?

[busterhymes]

cam box cover gasket the ,there paper ones m8 10 min job to change, only other cause carelessness when topping up oil :)