I can't find a link to enroll and, most of all, there's no "ENROLL IN THIS COMPETITION" button in the UHC website (https://www.uhcapps.co.uk/competitions/).Enrollment - ENROLL HERE (link to follow)
You must be a UHC member in order to take part in this competition. To become a member, click here and follow the instructions.
If you're already a member, click here to view the competitions page, then click the "Enroll In This Competition" button next to Opening Day.
You must be enrolled in the competition prior to starting a hunt from which you wish to submit scores.
There should be 11+ hours to go, according to UHC.