I assume that the anagram of the extra letters is an instruction of how to enter the nine special clues in the grid which means that the extra letter in 12 down is "c" but I don't have any idea what the original entry might be. Any hint would be most welcome. Thanks in advance.
So annoyed with myself. Completed the grid but dont know the solution to 43A. I know how to get it, but dont know what the answer is, or, therefore, the missing letter. :(
I very rudely did not introduce myself, I think this was my first post. I love crosswords, but rarely finish these tough ones. They are great fun nonetheless. :doffs hat: