Why 48 VLS cells was not enough

Did British missile doctrine assume one missile per target, and why did some designs settle around 48 VLS cells?

The Royal Navy used the same basic two-shot standard as others, and 48 cells reflected what was funded rather than what the panel considered ideal.

British practice did not assume one missile for one target; the common standard was a paired shot. Redirectable missiles could alter the calculation within a mass attack, but they did not make 48 cells an ideal load. The figure reflected what procurement would fund. NFR90 studies also assumed at least four air-defense ships around each carrier, so the cell count only made sense within a larger task-group design.