Some have used their favorite .303cal SxS chronographing 175gnRN 2000mv and drilled their eland dead at 195yd.
There is no right or wrong with your choice vs his.... he wanted to hunt with his .303cal double and accepted what shots
he could and shouldnt take, the PH in his judgement accepted his choice and guided him onto success.
I would rather hear about hunts like that, than the one where a client wanted to bring 'enough gun', then completely misses
his record book jumbo at under 15 yds with .500cal...the fool was probably mind drunk on too much Ruark and Mark Sullivan.
Well, I've collected a few head of game with a sporterized Lee-Enfield .303, but I've never seen a double .303 nor a 175 grain load for it. 180's were the most common load when I grew up, although IIRC C.I.L. made a 174 gr load as well.
I've interviewed quite a few PH's over the past 4-5 years for a project I'm working on, and they almost all tell me that the vast majority of their clients these days show up with a rifle they are quite competent with, regardless of caliber. I wonder if the tales you're referring to are just that... tales, not facts. One PH told me that 25 years ago it was not uncommon for a man to show up in camp with a brand new rifle he didn't know how to handle, but that that has become a rare thing in the present day.
