I am surprised as well, i can understand brakepads and other consumable bits not included, but a mechanical cable would be expected to last as long as the car.
I remember you telling me this was going to a be an every day car for you, this is out of the ordinary for a typical Morgan owner. You are perhaps only expected to do 5k max in your warranty period.
Can't remember the details of my Sport warranty but i am sure you are studying yours
Best of luck