I, too, was confused by what the compiler was getting at.
I think there is red herring in the instructions.
Overwiting the letters in the top and bottom rows is fair enough, but it only indicates that the successor has the same number of letters in his name as the out-going presenter, and that one of the letters in his name is positioned at the same place within that name.
The letters indicated by the coloured squares are an anagram of two words; these reveal where they both work.
What the compiler wants you to do is merely write down what the anagram reveals under the grid to complete the submission for the competition. (He doesn't seem to require the overwritten name).
I hope this helps your dilemma, not confusing you even more so.
Perhaps you can help me by suggesting:-
29a. They have split what Members abused (4)
I have E_E_