Wouah !! awesome ! I had never seen this longicorn outside the typus!
This is my opinion and I think it's him! From Pseudocentrus subinermicollis Breuning, 1958 endémic to Cape région. Normally there should be right in front of this black-brown fascia post middle an agglomeration or a fascia composed of white silks that I do not see on your specimens? Despite everything else seems to match!
Yes ! On the typus we notice that the anterior part of the black fascia is composed of white silks. On your first specimen where the black fascia is very clear, I have the impression that the picture is slightly lighter than the rest of the body, which is brown. In any case, it is this species. Everything seems to match except for this white pubescence just before the black fascia.
If it's like the African Exocentrus variability is largely present For me Pseudocentrus subinermicollis Breuning