Tore down the bulk of my engine today under adult supervision.
Glad I did, the camshaft needs grinding and the followers need reconditioning.
The #6 gudgeon pin and a few other fittings were removed with some LPG encouragement. There have been some sealing complications too, so there's a chance the crankcase will have to be machined (hope not). The cylinders were previously honed, but the rings have 600 TTIS, so they'll get replaced.
The engine is mostly stripped of paint now, so it will look as good as new by the time were done.