Jadzia49, it's not the initial letters of the extra words, it's the initial letters of the words either side of the extra words in the clues. These give an instruction and include the poet's name.
Two clues are very misleading. In 19a 'smuggler's' is superfluous to the definition since the Chambers entry for the answer makes no reference to 'smugglers', but it is not one of the intended extra words. In 24a, 'seen' is extra to provide an essential SI, but it could easily be taken as integral to the definition. When setter's use an extra word gimmick the extra word should be unambiguously extra. This isn't.