@Samanway and @Naveen thanks for the suggestions guys, my issue turned out to be due to a misconfiguration in my helm values manifest. I was trying to get this working by just modifying the connections section and adding the blob storage connection string within connections. Also I had the connectionsTemplates section commented out.

I thought I'd get the connections part working first and then use the connectionTemplates, but it turns out both sections need to be present for this to work.

      connections:
      - id: azure_blobstorage
        type: wasb
        description: connecion to azure blob storage for remote logging
        extra: |
          {
            "wasb_conn_id": "azure_blobstorage",
            "connection_string": "${AIRFLOW__CONN__AZURE_BLOBSTORAGE}",
            "is_encrypted": "false",
            "is_extra_encrypted": "false"
          }
      connectionsTemplates:
        AIRFLOW__CONN__AZURE_BLOBSTORAGE:
          kind: secret
          name: airflow-azblobstorage
          key: key