Police are appealing for witnesses after a Porsche Cayenne was stolen from a Mornington car yard a week ago. The white 4×4 Porsche, bearing registration plates ABF 179, was stolen between 7.30pm on March 9 and 7.30am the next day. Over the past two nights patrolling police have seen the vehicle a number of times in the Frankston and Seaford area. Due to the erratic behaviour of the driver, driving at high speeds, disobeying traffic control signals and travelling with no headlights on, police have not been able to intercept the vehicle. The Porsche has been seen on the Dandenong-Frankston…