Why Victorious was rebuilt before Implacable

Why did the Royal Navy rebuild Victorious instead of one of the newer Implacable-class carriers?

Victorious served as a test case, but the reconstruction's expense meant the Navy could not afford to repeat it across the rest of the class.

The reconstruction was an experiment before applying a similar approach to other carriers. The project proved so expensive that rebuilding the remaining ships became unaffordable. It is a short but useful illustration of modernization risk in a constrained navy.