Should the Type 26 and Type 31 swap main guns?

In hindsight, should the main guns selected for the Type 26 and Type 31 frigates have been swapped?

No; the Type 26 can use its larger gun in amphibious and full-spectrum naval operations, while three 76 mm guns would have suited the Type 31 better than a simple swap.

The Type 26 is treated as a full naval frigate with work beyond anti-submarine escort. It would help clear the waters for an amphibious operation, and its larger gun would then be available to support the landing force. Its ability to support that weapon is another reason to retain the fit. For the Type 31's air-defence role, three 76 mm guns are the preferred alternative to the mixed armament selected.