Tom
We have made some changes to Kingston Heath but not to the greens or the approaches. Graeme did all that work in his time (1982-97) including new greens at 6,13 and 18 as well as the dips in front of 7 and 14. I think he also changed the back of the 10th green.
We added the 19th (which they use in tournaments in place of 10) moved the tee back at 12 and as a consequence moved the bunker, removed the centre bunker at 11 and redid Graeme's fairway bunker at 18.
I'm not sure when you last saw it but in the last 5-10 years they have added tees at (wait for it!) 1,2,3,4,6,11,12,13,16 and 18.
It has certainly been hacked at a lot since 1926 but the changes seem to have not hurt the course in the eyes of the critics. As a club they have never been afraid to make changes - starting with MacKenzie's removal of the 'blot' of a 15th hole and its famous replacement.