ginge and scarlet
Thanks for your late night help. I have got it! On Google well into the early hours, I checked Redding, who I had not heard of, and I thought the change must be to a song , probably Red something. Eventually trying "Song Red din" I got Red Dinosaur song by T-Rex.
Thats it - Dinosaur requires the 5 cell changes, and even an old dinosaur like me has heard of the group T-Rex. The 14 letter "re-interpreter" puzzled me, but I got it. T-Rex is "re-interpreted" as Tyrannosaurus R. We are used to R for Rex and the setter could not get an X in the grid. I have found the letters in the grid.
Brilliant puzzle.