In short, Snuffy is buggered. RIP.
It turns out that Snuffy has suffered significant engine damage, we are unsure how it happened, but all indications are that it has been dusted, not only are the rings and bores stuffed, but the crank bearings appear as though they have done 600,000km, despite only having done just shy of 100,000km. This implies some crap (dust) has made it into the oil and gone through the engine.
So now I am looking down the barrel of a full ground up rebuild, like what I did in 2010.
Its frustrating being here again, we did all of this in 2010 after I stupidly left the sump bung loose. When we built it then we did everything properly thinking it would last me far longer than I would likely keep the car. Apparently not.