45 miles off the Lizard is a fair way across the channel. Perhaps its was in the French region for SAR responsibility. Perhaps French helos would be quickest on scene and French hospitals were closer than English ones in terms of getting casualties to aid asap...?
I suggest there is unlikely to be a conspiracy here. Why not ring Falmouth CG and ask - after all, you pay their wages!!!
Another point to consider. No doubt if, purely as one example, a British vessel sank 10 miles off the French coast at the western end of the Channel the British media, especially regional media, would report it as being 50 miles off the coast of Cornwall rather than mention the distance to France!
I would also add that the French have plenty of "long range" maritime experience, and still have assets to do it!!