Ok, so looking at pictures of some other 2.25D engines (like the one attached) I notice they have an oil filler neck at the left of the engine as you look at it from the front of the bonnet. Mine doesn't have this so I have been topping up the oil from the engine breather cap on top of the rocker cover. There seems to be nowhere else to put the oil into. Are there different evrsions of this engine with different oil fillers?