Prior to WWII I would call British self-loading pistol cartridges with CNCS bullets an unusual thing. The preponderance of these rounds are CN, with an occasional plain brass jacket. Most of the GM jackets are more modern rounds, but still GM, not GMCS. Of course during the war I believe you find both.
The British “All range” bullets, at least the ones I have, are all CN; none are CNCS. Only the German version is, which I don’t find unusual at all, as the Germans made much more use of basic steel bullet jackets, whether GM or CN coated. Of course, they also made lots of ammo with just CN and GM jackets.
Unfortunately, I have never had one of the WR capped rounds in my hand, so I simply have not idea of whether or not they are magnetic. Based on no knowledge of them, but a pretty fair selection of British auto pistol cartridges in my collection, I would bet that they are non-magnetic. But, I wouldn’t bet more than I could afford to lose. :-)