Dorset, Devon, winding narrow lanes, up hill, down dale..............as Tigger would say - this is what automatics like best!!!
Well, not in the same words perhaps, but the big thing about an auto is that it does the changing so you don't have to.
The Cmax, as I recall, uses a variable speed system - modern descendent of the old variomatic system. I think it has 7 pre-selected ratios you can use.
My Kia - old TC type - has a manual sequential shifter so that you can take control if you want - good for engaging engine braking on long hill.
Go back to a manual? If your maker wanted you to drive a car with 3 pedals you'd have been given 3 feet!