Leaking oil from the top of the engine? Around the 90/100 thousand mile mark the seal on the cam cover to cylinder head will start to fail. This involves 20 parts! 6 spark plug bosses, 1 cover seal and 13 seals on the mounting bolts and all necessary! Be aware that tightening the bolts does no good as they are shouldered and are non compressible.
Also, be aware of the nut on the back of the generator brace behind the rubber bush that is located in the cam cover casing. If the nut is missing, the generator/alternator is secure but the rubber bush will put pressure on the cam cover to move rearwards causing not only leaks at the back but also where the section of the cover changes after the cam chains. The nyloc nut and washer are probably missing on lots of DB7 i6s.
So that covers oils leaks on the r/h/s of the engine. Should you have oil leaks from the l/h/s side the favourite is the 6 orings, 4 on the transfer pipes and 2 on the cooler lines to the block. The orings go hard and the section changes to square!