Just to keep the arguements down. The vessel was in the French sector so the French RCC had primacy. Yes Culdrose would have been slightly quicker to get to the scene but it was the French call and by the time they would had made an official request to the UK ARCC the time difference would have been negligible.
The first rule is make a decision and a plan and get something going rather than think too long and forget to get a helo airborne.