Why wartime Britain would move beyond Implacable

Without Churchill's interference, would Britain mass-produce Implacable-class carriers like the American Essex class?

Probably not; the major expansion point comes late enough that Britain would build Audacious-class or equivalent improved carriers.

The need for carrier volume becomes acute against Japan in 1942 rather than at the war's opening. By then Implacable is already entering the construction and service pipeline and designers are working on the next generation. Britain would therefore avoid freezing a large wartime batch at the earlier standard. Additional volume would more plausibly come from Audacious-class ships or an equivalent improved successor able to reflect Pacific operating lessons.