To all, thanks for your help.
In the end after a lot of experimentation, I gave up getting it working as is, and upgraded to the latest 6.5 patches on the Hosts. This worked. The Windows 2019 install routine now sees the local disks.
(To any who felt this should have been the first step, I didn't see any caveats about patch level or similar in VMware's advise. Only Versions 6.5, 6.5U1 and 6.7 as qualifying levels for being compatible with Win 2019.)
And I was trying to avoid these updates because within a week, I will be upgrading to 6.7, and I didn't want to have to run though the hosts twice if I could avoid it.
Again, thanks to all who contributed.
Geoff.
