Lots of cleaning and measuring today.
The block has no obvious damage, the core plugs were uncorroded, so their removal was in retrospect, of no benefit. Chasing the tapped holes with a tap produced no surprises.
I don't think the cam shaft bearings are worn, but I need to read the manual again.
I found that measuring the bearings was difficult, but ended up getting consistent measurements that suggested that there was no ovality in them.
The piston bores still have cross hatching throughout, so again, I'm thinking that there's little work to be done there.