The customer authorization (provided in the link you clicked) is out of date, and does not entitle you to use the Blended Threat service.
https://www.gov.uk/guidance/auditing-if-theres-no-brexit-deal?utm_source=2dde0056-92a8-49e2-a568-f2d5e879ee4b&utm_medium=email&utm_campaign=govuk-notifications&utm_content=immediate