Charles A. MacKenzie was Alister's younger brother. He was president of the British Golf Course Constructors firm which carried out most of Alister's work in the UK and Ireland after the Great War.
The brothers had a falling out in 1926 (Charles' wife and Alister's first wife were good friends, and the younger couple sided with Alister's wife in the split). After that, Alister started working internationally, and Charles did some design work in the UK.
Charles' design work was not too well documented, and there is confusion as to which projects he designed, because clubs today prefer to remember his more famous brother as being involved somehow. All you really need to know is the date of construction ... if it's in England after 1926, it's Charles's work; if it's before 1926, Alister was the designer, possibly with Charles making some contribution (but likely not much of one).
What is the course with the lost MacKenzie holes?
And are you positive they couldn't be managed today? Some golf courses coexist peacefully with SSSI.