Kev, as others stated, due to the shape all Morgans suck the exhaust into the cabin, may be the ones with a spare wheel mounted suck a big amount of fume in at the spare wheel area before it reaches the cabin. Some „work arounds“ are a possible option, e.g. opening the side windows to reduce the amount of under pressure in the cabin.
When your P4SS has the latest update developed by Omex it should be reduced to a level you should not notice it, almost. Before this upgrade, the engine was running too fat and the cat could not sort it. Now, it should be fine when the engine is running leaner.
nick w, I have exactly the same thought, if the cat works properly we do not smell it but it will take the same path into the cabin. It is also weather dependend in my experience.
