Mayo Oldiri is a spanish outfitter having the largest areas in Cameroon, either in South (forest) than in North (savannah.

They are doing pretty good.

Mayo Oldiri is in stark contrast with other outfitters. The rest are "family" outfits, the outfitter being the PH, and theses guys having their area often for 2 generations (Vannier, Guerini, Betaille....).

Regards to the PH. 3 French senior PHs with all the possible credentials. One of them is Hervé whom I hunted with in CAR twice. 2 others are spaniards and not registered in the ACP, the PH french association.
Your PH is mentionned as "sennior" and is a Zimbabwean PH.
None the less, hunting the Derby eland is no big deal as far as You can walk. A premium is the density of roads and trails to point the best tracks and stalk the eland.
Good luck.