The area around this was oily, dirty but not really wet. Anyway having looked at EPC and WIS I decided just to remove it and see if there was a gasket behind. There wasn't somewhat to my surprise, but neither was there much oil there. I'm assuming there is a seal somewhere inside the head which prevents oil escaping and pressures in the camshaft cover are not that high anyway. So I intend to just reassemble after cleaning up unless I should be doing something more complex. If anyone has the torque figures for the three fasteners I'd be grateful