I had the same problem with mine, when i put the engine back in last month i used all new gaskets including the crankseal one, but it all together and the bastard leaked oil, i changed the sump gasket twice and it didnt make any difference, looked at my flywheel and it was covered in oil!, in the end had to take engine back out to replace the crankseal again,

this time i brought a new carrier to put the seal in and its been fine now! not a drip!, i always use a bit of sealer around the half circle cut outs of the sump, and around the oil pump coz ive done one before without sealer and it pissed out everywhere!!