I'm new to all this really but I believe that you can.
I hold the BA Premium Card and have just successfully obtained another card for MrsE. This card is in her own right and we are both supplementary card holders for each other. If you refer for someone I think you get 9k and the applicant gets 26k but may be wrong. You could also try a direct application through topcashbsck as they were offering £47.25 which converts via Tesco to about 12k giving you 37k overall.
As I said though, really new so may not be the best way?