This was a quick solve as I guessed the author and title of the poem almost immediately, realised that there was a key 11-letter word in the poem (though I didn't know that the author's spelling was not the same as the spelling in Chambers), and spotted a couple of answers to the thematic clues and a couple of the jumbled sequences in down clues that confirmed everything.
I suspect that most people over a certain age came across this poem at school (and probably had to learn it off by heart), but it's neat that Hedge-sparrow noticed the possibilities of the various thematic items and the ability to fit the items listed in verses 2 and 3 of the poem into the grid in symmetric positions.
Straightforward clues (I'd also noted the slip-up with 23d with a missing cross-reference in Chambers to the alternative spelling that actually contains the meaning in the clue), but I agree with Meursault that there's less satisfaction in fitting a list of words that we can identify from the poem to wordplay-only clues than actually solving the clues. As Meursault notes, the puzzle should have been set several months ago, given the thematic hint provided by the title.