1970s Leander frigates transported to 1939

Would replacing 1939 Leander cruisers with 1970s Leander frigates help the Royal Navy?

It would sacrifice cruiser hulls but create an extraordinary ASW and air-defense advantage, with some ships adding Exocet and Sea Wolf.

The hypothetical exchange would leave the Royal Navy short of cruisers while greatly improving its ability to hunt conventional submarines. Later Leander fits add helicopters, sonar, Limbo mortars and, on some ships, Ikara. Sea Cat and radar-directed 4.5-inch guns would present unfamiliar threats to World War II aircraft, although maneuvering targets could still defeat Sea Cat. Exocet is expected to cause a mission kill through superstructure damage; the claim of certain battleship-armor penetration is explicitly withdrawn. Wartime Britain could plausibly reproduce or support guns, mortars and some sensors more readily than the advanced missiles. The result depends on the frigates' individual fits and the number introduced into the scenario.