War modifications (from Wiki)
(This information is a guide only from that other timeline we do not talk about here) It is unlikely that the early war losses Codrington, Acasta, Acheron and Ardent received any major alterations. In 1941 the surviving ships had the after funnel cut down in height and the after torpedo tubes replaced by a First World War era QF 3-inch (76 mm) 20 cwt anti-aircraft gun on mounting HA Mk. IV; a somewhat token addition. More of an improvement was landing 'Y' gun and the minesweeps and fitting Asdic and racks and throwers for a 10-pattern depth charge salvo, 70 rounds being carried. Two 20 mm Oerlikon guns were fitted, one in each bridge wing. Achates had 'A' gun replaced by a Hedgehog anti-submarine (A/S) mortar and had the centimetric Radar Type 271 for detecting surfaced U-boats. Others had metric Radar Type 286F or 290 added, the former of which had a fixed antennae array and required the ship to be turned to change the bearing down which it scanned. By 1942, the Canadian ships generally had 'B' and 'Y' guns removed, Radar Type 286 added, no torpedoes, a 12 pdr gun, six single 20 mm Oerlikon guns and stowage for 141 depth charges.
The four Southern African ships were completed in early 1931 and were transferred to SAN as escorts to the new battlecruiser Transvaal. The ships were used during their war service as escort command ships to the older M, R, & S class destroyer escorts. The Beagle shown above was typical of the SAN 'B' class destroyer conversions.
By 1943, Antelope had Radar Type 271, and Type 286 and 290 sets, where fitted, were replaced with Type 291. The 12 pounder gun was removed around 1943 and High Frequency Direction Finding (HF/DF, or "huff-duff") was generally added. The single 20 mm guns in the wings were replaced by Mark V powered mountings for twin weapons, the singles replacing the ancient 2 pounder guns amidships. In 1944 Active, Anthony and Antelope receiving a pair of 6 pounder / 10 cwt QF Mark I guns on a Mark I* mounting in lieu of 'B' gun. This automatic weapon was fitted for dealing with E-boats on east coast duties.