AFAICT the two processing steps that have the most impact are the super fine milling that is used to create modern flour, and the removal of the bran from the flour. Those are likely the same whether you have Chorleywood bread or homemade 4 ingredient bread.

I suspect that Chorleywood bread made with stone ground whole wheat flour is better for you than home made four ingredient white bread. (with the caveat that Chorleywood probably doesn't work with such flour).