I get what you mean but Brittany Ferries is the group name which comprises of the bank, SOMABRET, SOMANOR & BAI. The first three get the lions share concerning their ships and BAI get all of the money from theirs.
The charter fees are low hence why there was an investigation triggered by P&O stating that the financial arrangements gave BAI an unfair advantage but ultimately it was decided that the bank and Societies would never have an intention to charter them to anyone else on routes they serve so the point was moot.
The Societé chartered vessels are paid for from the income they generate some of which is given back to BAI to cover maintenance. All four within the group earn a profit from them.
Bretagne cost £55m, in today's money that's around £136m. I think they've all done well out of her and the arrangement has meant that BAI still exist and have gone on to bigger and better things.