Gannets
Any idea of using the Gannet in the Falklands was pie-in-the sky thinking, I'm afraid. While the Gannet was capable of a free take-off (ie without the use of a catapult), it wouldn't have survived a launch over the ski-jump.
Re the flaps. It was usual to use full flap in most aircraft off the cat, and I assume the Gannet was no different. After all, it gave max lift, and drag is hardly a problem when you have several tons of boost from the cat behind you.