An early DDG(X) programme and a larger Type 45 missile fit

What if the United States had built the proposed destroyers mentioned in the question, including DDG(X), in the early 2000s?

Britain might have responded by enlarging the Type 45 missile fit, with forty-eight additional Mark 41 cells suggested.

In a counterfactual about larger American destroyers being built in the early 2000s, the British Type 45 programme is running at the same time. The suggested reaction is to increase Type 45's armament to keep pace. One possibility raised is another forty-eight Mark 41 launch cells in an added aft section. This is a speculative response to the scenario, not an identified approved Type 45 modification.