Wartime modifications involved adding a Type 279 radar at the masthead, a primitive metric wavelength air warning set, later replaced by a Type 286 then a Type 291, as they became available. A Type 285 radar was fitted to the rangefinder-director on the bridge, this was a metric set and could provide target ranging and bearing information. The centimetric Type 272, a target indication radar with plan position indicator (PPI), was fitted to the front leg of the foremast. Following the loss of "Latona" to air attack, the surviving ships were re-armed to remedy the shortcomings in anti-aircraft defence. Six single Oerlikon 20 mm cannons were initially added on P Mark III pedestal mountings, although these were later replaced by powered twin Mark V mountings. "Ariadne" and "Apollo" had two twin Mark IV "Hazemeyer" mountings for Bofors 40 mm guns sited amidships, replacing the pom-pom in 'Q' position, and these mounts carried their own Type 282 Radar for target ranging; "Ariadne" had an additional "Hazemeyer" mounting in 'B' position, replacing the 4-inch guns. In July 1945, "Ariadne" was refitted in the United States for far eastern service, when the Bofors mounts were replaced by American pattern models (Mark I) with off-mounting "simple tachymetric directors" (STD) fitted with Type 282 Radar and the Oerlikon mounts regunned with Bofors guns (this combination was known as the "Boffin").