A heavier gun fit for a Type 31 frigate

What gun armament would you prefer for Type 31?

The preferred fit is a five-inch gun with 57 mm and paired 40 mm mounts, although this is an idealized arrangement.

The idealized Type 31 arrangement uses a 5-inch main gun, a twin 57 mm weapon, and twin 40 mm mounts aft. Each calibre serves a different layer instead of asking one gun to solve every surface and air-defense problem. The arcs of fire could bring several systems onto a threat approaching from a favorable quarter. Cost makes this arrangement substantially more ambitious than the likely service fit.