Hi Richard. 
 
I don't know you or how you go about the job & I can't tell from your post, what tests have been carried out. I do understand the logic behind the decision to replace the crank sensor. 
 
The reason for my last post, was that I think you would benefit by scoping the sensor instead of guessing about it's functionality. 
 
Please don't take this as a criticism, as only,three years ago, before I had a scope, I too was pi55ing in the wind & making ill informed diagnostic decisions. Imagine the confidence you would have in the case of this Clio, if you could visualise the signal quality from the old & new sensors. It really does take much of the guess work out of many diagnostic tasks.
 
The scope is one of those tools that, once you have become familiar with its use, it will have you wondering "how the hell did I manage before?" The answer is unfortunately that "It was mostly guesswork & pi55ing in the wind!" 
 
It maybe that you have done some testing & I have misjudged the situation, if so then I apologise. 
 
Regards 
 
Dave