NitroX
I would highly recommend the Chapuis in 470. I helped a guy sight in and develop reloads for a Chapuis 470. His rifle shot and handled very well. A good friend of mine has bought one in 470 but has not taken delivery of it yet I will also assist him in loading for it so I will keep you posted on those results. I have had a 9,3 Chapuis for @ 5 years and I have shot it @ 1000 times. It is still as tight as the day I bought it. I have hunted with it quite a bit and the wood and steel finish has held up well.
You are correct a 470 is the best calibre for a working PH.
Another very nice thing about the Chapuis is they [most are here in the USA check for sure before you buy a particular rifle] already cut for a scope mount. It is a simple four screw attachment. The mount on my 9,3 always goes back to zero, and I have 2 scopes fitted for it. He might prefer a scope for some situations. When the scope is removed you can not see the bases when aiming with the iron sights.
While I prefer the Nostalga of a British double for my own hunting if I was going to PH I would use a Chapuis 470 for a work gun. You can also get a set if 12 gauge bbls fitted to it.
I have been very,very happy with my Chapuis 9,3.