Strengthened decks were not the same as armoured carrier decks

Did British light fleet carriers have armoured decks?

They had strengthened decks and some useful robustness, but not the armoured-deck scheme of Britain's purpose-built armoured carriers.

British light fleet carriers had strengthened decks rather than protection equivalent to the armoured carriers. That construction could still make them more robust than some American counterparts without turning them into armoured-hangar ships. It also cautions that quoted and effective thicknesses can differ depending on which structural layers are counted. The useful distinction is between a deck made strong enough for service loads and a protection system designed to resist attack.