In May last year, the International Chamber of Commerce ruled San Leon subsidiary Aurelian had to pay £13mln to Avobone, its former partner, related to the prospect at Siekierki.
Aurelian lodged an appeal against the ICC findings to the UK Commercial Court in October.
The findings of the court were that Aurelian's leave to appeal was dismissed.
Accordingly, the original award stands. San Leon is conferring with counsel on its options.