So a few days later and I run the engine with the front main bearing cap off. I'm not going to show you a picture, because there would be oil everywhere, but you can see from this shot with the cap loose that there is oil there; with it off it gushes out:
And here we have a new spring just arrived from Draganfly, about 25% longer and somewhat stiffer than the old one:
And here we have an oil pressure gauge showing a previously unreached figure, 55 psig, at tickover - engine relatively cold (about 5 minutes running). Thats more than 50% up on last time.
So now we need a road test. Yippee!