For whatever it's worth now, the law's having perhaps changed, I hunted northernmost S. Africa, very near the Zim border, about 20 years ago, using a .45 muzzleloading rifle and 540 gr. bullets. I was used to shooting it with Swiss 1.5 F here in the U.S. and much think the Safari host got Swiss BP and caps for me to use on my hunt, not Wano.
I"ve tried various BPs over many years and used Wano little if any. Lots of experience with granular Pyrodex, tho, from previously living 31 years in Hawaii with no BP available.
Of note: for any sidelock ML rifle using caps with granular Pyrodex, Spitfire nipples -- with their hollowed-out base and narrow flash channel in the upper portion -- like the better old time nipples -- are best for reliable ignition of granular "RS" (rifle/shotgun) Pyrodex. (Or use a musket nipple and cap, which has the power of a 209 shotgun primer.) And always hold the barrel up vertical after pouring the powder down the barrel and give the breech three stout whacks with the heel of your hand, to get some powder grains down into the flash channel at the breech. Good plan with BP, too!
Aloha, Ka'imiloa