Britain improvised carrier transport with the Gannet

What was the British equivalent of a dedicated carrier-onboard-delivery aircraft?

There was no fixed equivalent; adapted Gannets could perform the transport role when needed.

British planners examined carrier transport options without settling on a direct equivalent to the American C-1 Trader. That left logistics to be covered by aircraft adapted from other Fleet Air Arm duties. An anti-submarine Gannet could have its mission equipment removed to create useful cargo space. The same equipment could be reinstalled when the airframe was needed again for its primary role, offering flexibility but not the capacity or routine availability of a dedicated carrier-onboard-delivery fleet.