… just answering my own post in case it’s helpful to anyone …
Should I uninstall HSO and reinstall the soundset from Cubase 6 (the last version for which I have install disks)?
I then successfully applied the 1.0.1 update from the downloads section of this site
I haven’t uninstalled the old one yet, but the point is the soundset is a different beast from the old .hsb files, even though it’s the same noises.