Not for long though, oil leak again. Which meant (depressingly) the N/S engine mount, intercooler pipework, exhaust downpipe etc all had to come out. The turbo oil feed adaptor had bottomed out in the block - could tell because the black anodising was stripped off the first couple threads on the adaptor. Using a spare crush washer/copper washer, and loads of PTFE tape the joint was remade, we restarted the engine while it was half dangling on the crane and no leaks.
All back together, here's a video of it finally starting and running well, no leaks, nice and smooth.
Next jobs - trimming inside and getting an exhaust made.
p.s. excuse wobbly camera work on startup, watch the exhaust you'll see why! That was much louder than it was on video.