Whipped off one of the big end bearing caps..... finally, some good news... absolutely nothing wrong with the bearings!
Crank journals are perfect too Judging by the state of those it looks like I may have caught this just in time.....
So the oil pump is fixed and back together, refitted, filled it with oil, spun it over on the starter and I'm now getting good oil pressure
Yay! Oil light goes out instantly.On starting the engine it sounds absolutely sweet, no untoward rattles, rumbles or noises. Celebration time
Many thanks for all the guidance and good counsel - you've definitely helped save this engine and this little 124 Spider is one step closer to making it back to the open road.....