You’ll be surprised to see that all Battle class & Daring class destroyers are missing their squid mortars, egregiously you can see the reloading mechanism on the deck but the squid mortars are plated over.
The Type 41 AA Frigate & Dealey class Ocean Escort are the only two ships with squid mortars themselves actually modelled on deck (the latter is also missing GFCS mechanics an thought modelled on the ship), but the devs have be lazy to actually model them as physically working systems it seems.