hi firstly is the vecra 16v or 8v. if 16v its a big job for the experienced mechanic 8v is easier but again experience required the most likely cause of the loss of oil is the valve stem oil seals. this will require remioval of all the valves involving special tools and quite a lot of time.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cars.