Invalid TileJSON error in QGIS 3.10-5 (Windows 10 1909)

[richard-thomas]

When I try to connect to either one of the pre-installed servers or the OS Open ZoomStack (http://s3-eu-west-1.amazonaws.com/tiles.os.uk/v2/data/vector/open-zoomstack/config.json), I get error:
"The field 'vector_layers' is required but not found. This is invalid TileJSON"
even though if I browse to that URL, it looks fine.

I have added the v3.2.2 plugin using QGIS 3.10.5 plugin installer (installed using the OSGeo4W64 installer running under Windows 10 1909). I had the installer working fine a few months ago under Windows 10 1809, with an older version of QGIS3 (not sure which).

I am somewhat unclear about the instructions which now seem out of date (or perhaps not right for the OSGeo4W64 installer). In the instructions provided on the Wiki, the first link does not need to be made as the plugin already is located in directory:
C:\Users\Richard Thomas\AppData\Roaming\QGIS\QGIS3\profiles\default\python\plugins\vector_tiles_reader
For the second link, I did the following as not installed in "Program Files":
mklink /D "C:\OSGeo4W64\apps\Python37\lib\site-packages\qgis" "C:\OSGeo4W64\apps\qgis\python\qgis"

Is this a bug, or am I missing something? (e.g. some additional library/package within the OSGeo4W64 install)