The answer proved to particular to Sitecore 10.2 (My mistake was I had been looking at a 9.3 guide).
Key steps in the above article are:
In the App_Data\items\
App_Data\items\
folder, make a copy of the Web folder.Rename the copy of the folder and the .dat
.dat
file inside it. Use the database name for the folder (for example, web_previewweb_preview
) and use the database name within the file name, so it is similar to items.web_preview.datitems.web_preview.dat
).
Once those files were created the new target began working as expected.