Oil leak!

Iv got a oil leak on the left hand side of the block somewhere behind the alternator!
Can't quite see where it's coming from as it's quite gunky! I don't think its coming from the head gasket, as it starts a little lower.

What could be the cause of this?

Also there looks Like there is oil dripping off the alternator so the oil must be coming out with bit of pressure!

Is this the engine which was stood for about 10 years not running? Its probably an oil seal which has dried up and/or cracked.

Yeh it's been stood since about 1999/2000! What seals are around that area? Apart from head gasket and sump?