This late model BMW 320i had an oil leak which was caused by a defective cylinder head cover gasket (also known as a rocker cover or valve cover gasket).
A local specialist European car dealer in Girraween dropped the car into my workshop and I was able to replace the gasket for them promptly for a fraction of the cost that a BMW dealer would have charged.
I am a specialist in BMW and would welcome you to try us for your next service or repair.