Oil leak coming from somewhere below the exhaust outlet manifold.

When running the engine, oil is slowly dripping from somewhere below the exhaust outlet manifold and on to the U-bend of the exhaust where it is then evaporated into smoke. The coolant level is being used at a rate of 2 or 3mm per 25 miles. The car is a 2 week old purchase and was MOT'd upon purchase with NO advisories. But a day later we then found it to be over filled with oil by approximately 5mm and with the smoking also. We informed the dealer and mentioned the overfill of oil to him. He said that this overfill would be ok and that that is why the oil is leaking and causing a bad smell, and to keep an eye on it for couple of weeks just till the oil burns off and is not overfull anymore. I have not yet mentioned the water issue to him. The car runs ok apart from the smell of burnt oil. The oil and water pressure are ok and clean exhaust fume also. Thanks, Please can help! Regards, Michael.