Why an Irish Channel squadron would not need cruisers

Would Leander- and Arethusa-class cruisers make sense for a dedicated Irish Channel squadron?

No. Channel patrol would normally be a destroyer or flotilla mission within the Home Fleet, not a cruiser-squadron task.

The proposed formation lacks a mission demanding its expensive cruisers. The Irish Channel is a limited operating area whose patrol requirements do not justify Leander- or Arethusa-class ships. Destroyers could perform the work, whether as individual patrol ships or a flotilla attached to the wider Home Fleet. Force structure should begin with the mission rather than with a preferred ship type.