Hunt-class vessels had themselves acted as motherships for mine-warfare systems. HMS Stirling Castle supplies another platform for that work, but she is a single converted merchant ship. She is described as about ten times the size of a Sandown and lacks even that class's 30 mm cannon. Her transfer from the Royal Fleet Auxiliary to the Royal Navy does not resolve the concern about her light armament. StanFlex could have offered an arming option, though the counterfactual does not assume that this particular merchant conversion would necessarily have received module slots.
Notable Point · 24:24-25:56
Stirling Castle's mine-warfare role and light armament
A large converted merchant hull can carry mine-warfare systems, but Stirling Castle illustrates continuing concerns about numbers and self-protection.