Ok, thanks for reply.
Running this:
update-initramfs -u
update-initramfs: Generating /boot/initrd.img-4.15.0-towo.1-siduction-amd64
And rebooting from chroot gives similar error about 30 times:
Begin running /scripts/local-block ...done
And then it went on to suggest possible reasons for the error:
Check the command line:
cat /proc/cmdline
BOOT_IMAGE=/vmlinuz root=UUID=838239a...115a # I truncated UUID for here
Note: Previously, the root device pointed to dm-6 but I changed to UUID to test. Neither work and both give the same error.
Check for missing modules:
cat /proc/modules
Many show up but lvm does not. Should it?
Check /dev/:
ls -l /dev
Many show up including /dev/sda b c as expected, but there is no reference to dm-6
Not really sure about any of this, but it seems to me that since my root filesystem and kernel files reside in a LVM volume (as is my practise everywhere, including my Stretch install), is the problem that the initramfs environment can not see LVM volumes?
Thanks again for your help and this great distro.
-Steve.