The right to operate the multiplex (and therefore the rest of the space) was to be given to the highest bidder. S4C (who were already guaranteed their 'gifted' space on the multiplex), United News and Media and NTL set up S4C Digital Networks (each owned one-third of the company) and bid for the right to operate Multiplex A.
The right to operate the multiplex (and therefore control the entire space) was awarded through bidding. S4C, who had a guaranteed spot on the multiplex, along with United News and Media, and NTL formed a joint venture called S4C Digital Networks to bid for the rights to operate Multiplex A.