Taki, please don't misunderstand, I'm certain that Mr. Leeming is very knowledgeable when it comes to scorpions. I was a bit quick when I made the claim that he's not the right person to go to with this.
However, there is indeed a few errors in his book. Some obvious, some more subtle. I.e., the species Parabuthus leavipes is not an actual species. I have no idea where he's come up with this name, but I believe that the species he's referring to, is P. laevifrons.
Further, he also claims that P. schlechteri digs shallow scrapes under rocks, which also is not correct. He has taken this bit of information from Lamoral, but knowing the behavior of other Parabuthus species, this claim should have been examined further before being accepted. L. Prendini mentions the claim by Lamoral in his 2004 revision of the genus.
I don't have the book with me right now, so those two bits are all I can think of on the top of my head. This being said, I've enjoyed his book greatly. The point of it all was just to notify the OP that unless a DNA test is conducted, one most likely can't determine the species with 100% certainty.