oil on my new driveway !!

we have a 300tdi disco, that had a remarkably clean engine when we bought it. over time it has started to develop a few drips. Some from the rocker top, which we have cured by removing the silicone that somebody tried doing a botch repair with, and fitted a new rocker gasket. Some from the breather system which has now been removed , fully cleaned, refitted and all connections tightened. But the one main leak is from the oil pump itself. Firstly around the lower core plug for some reason, which has now been filled with an oil leak like cement, but it is still leaking from the seam, which is only held together by pop rivets ?? Is this the norm, (leaky pumps) or is there something I can do to stop the drips, last resort to buy a new pump. any help please ??