Hi @David Greenwood • Thank you for reaching out.
If I understood correctly, you want to remove the inaccessible Azure Active Directory B2C tenant from Directories+Subscriptions blade (https://portal.azure.com/#settings/directory).
If that is the case, you can go to the Organizations blade on My Apps portal (https://myaccount.microsoft.com/organizations) and click on the leave organization link next to the B2C tenant.
Once you successfully leave the organization and get the below message, you will no longer see the B2C tenant under Directories+Subscriptions blade.
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