Or even, Dryden, the setter might have used 'answer' in place of the first occurrence of 'entry'. I think it's fairly hard and fast that an 'answer' is a solution to a clue, which may or may not be an 'entry'.
I was sidetracked for a while by the penultimate sentence also, "The three-word phrase..." Having guessed at the first word, for some time I imagined that the other 2 words would be "...the letter", which makes an established phrase. Though I suppose that this was a fair deception, the preamble didn't state that it had to be an 'established' phrase.