The customer authorization (provided in the link you clicked) is out of date, and does not entitle you to use the Blended Threat service.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.ygam.org/bespoke-workshop-booking/?crb_workshop=07.04.21.%20Bespoke%20OL%20FULL%20Gen.%20London%20and%20Yorkshire%20(Sports).%2014:00