I've noticed this past while a small oil leak on the left hand side of my defender's engine (300tdi), around the manifold area behind the alternator. While it's not losing oil in any quantities worth worrying about, it's still a nagging problem that I'd like rid of. All I've done so far is hose it off to try and find the source, but I can't narrow it down, and it starts returning a few days later. The Rocker Cover Gasket was replaced last january by the previous owner due to an oil leak, if that info helps any.
Any suggestions as to what it could be would be helpful, as I'd like to take a look at it over the Christmas holidays, and (hopefully) repair it.