Engine oil leak !

I didn't do it as it was the garages responsibility but as I understand it you "just " need to remove the main crankshaft drive pulley and the seal is accessed. I say just because it is very likely that the crankshaft bolt is going to offer significant resistance. It is going to help to remove the radiator to prevent damage and improve access it is also going to help to have a heavy impact wrench gun. The problem is that the bolt has an integral flange that over time rusts itself to the pulley which combined with the bolt being torqued to FT makes life difficult. Some people have had to resort to the angry grinder to cut the flange off and have a chance.