A quick search suggests this is long planned and permanent, it gets a mention here:
https://www.glanllyn-newport.co.uk/wp-content/uploads/2022/11/newsletter-spring-2022.pdf
which includes the text (as of 1+ year ago):
"we are bringing
forward plans to close the junction between Bloomery
Circle and Baldwin Drive to vehicles and make this area into
a cul-de-sac as intended in the overall masterplan for Glan
Llyn. The road will still be open for pedestrians, cyclists and
emergency vehicles"
(which also suggests the main road is/will be "Baldwin Drive", which looks like could be set as tertiary).
This also seems to correspond with the overall site plan photographed here:
https://www.geograph.org.uk/photo/2794612