Summary
Resolution
Make a note of the Internal name for the customer or site you wish to filter by.
TIP: The Internal name is found in the Sage Provisioning Portal, for the customer this is found in the Customer data section; for the site it is found in the infrastructure section.
Open portal.azure.com and go to Resource Groups (or All Resources).
Click on Filter and select the required SPP Tag, leave the Operator set to == and enter the Internal Name into the Value field (ensure that all is deselected and the value field converts to a tick box selector), and click Apply.
TIP: Tags are also available for Product, Subscription, and Partner.
It is also possible to use the Tag filters to display related resource when looking at resource record by clicking on the required tag.