from the March ann looks like BPO have the right to acquite 75% of Frontiers shares. Frontier itself have an option to back into 5% from Otto's participating interest in the SC55 block, up to 150 days following the drilling of the first well. Plus buy back option on 15% of SC69.
Its currently not an "indirect interest", just an option.
presumably it'll cost a fortune to buy back in following a successful well on SC55!