Apart from the Hassbian welcome message not appearing via my SSH connection - the install seems to have worked & after waiting about 10mins - I can now access HA via the browser.
While I was waiting I noticed that a comment on the HA Installation page suggested the following
"…After initial boot an installer will run in the background, this will download and install the newest version of hassbian-config and Home-Assistant, this takes around 10 minutes to complete, after it has finished, you will be prompted to login
OK, so you can open your browser and see the HA welcome screen at your_ha_ip/8123, correct?
the download script already ran and is complete if you can access HA at port 8123.
there aren’t necessarily any files you need to download/install. the update of HA will (should…) take care of all of that. That’s the benefit of it being installed in a virtual environment. It is a pretty much standalone package. It knows what it needs and will install the correct versions separate from the base OS.