Working from memory rather than my notes which I haven’t looked at for years:
Quite a bit of the routing pre-dates MacKenzie. The 9th green that Tom refers to was called out for flattening along with many of the others in 1935 but perhaps never was. The 14th green pre-dates MacKenzie but in the Gibson routing (1907), it played from a different angle, approx tee position near today’s 7th green. Hence along the right side of the diagonal ridge in today’s 9th. 18th green pre-dates MacKenzie. So does the 4th (Gibson) and 5th (Old Tom).
One of the NLE MacKenzie holes was the 3rd which I believe played to the left of the dune that you have to hit the current blind tee shot over, probably eroded land where the beach car park now sits. 7th green site also was washed away but the intent of the hole was restored by Hawtree. The 8th is a completely new Hawtree hole. MacKenzie’s par three was much further to the right.
I can’t fully remember what other new hole corridors he added back in 1927 but in summary, this is what I can recall:
He rejigged 1-3 but in same rough areas, had nothing to do with 4,5,6 or first half of 7. He created 9, think 10 was approximately there. He created 11,12,13. Think he knocked through the dune to create the approach to 14. Can’t recall what he did 15 or 16. Believe 17 and 18 were old holes.