Alrighty,.. probably the same pan.
I have a line on not one but 2 oil pans now ( Sorry Rob, not the one on Ebay) and will fix this properly. In the meantime, after being told that the plug was tight and everything was right, the oversized washer (16mm vs 14mm I.D.) appears to have been skewed a little when the plug was put in last ( I didn't do it.) so, that was the source of a good deal of the problem.
It also turns out that the drain was tapped, but not drilled.
So,.. I think I know where things went wrong.
Once I have a proper Oil pan on her, I might just have someone else tap out this one, in case anything ever happens like this again. Even though, I've never stripped threads out of anything, stuff happens.