The Argies used French planes to fire French exocet missiles at the Royal Navy. They are our traditional, historic enemy, going back to 1066; Agincourt, Cressey, Poitiers, were all fought against the French; Marlborough fought with German allies, against the French; all through the 18th century the Royal Navy was tangling with, ( you've guessed it ), the French; Clive of India & general Wolfe fought the French; Wellington..... well you get the picture.
Let's face it, we took most of India and North America from the damned French, so they're hardly going to back us in a dispute over territoriality.