Though I enjoyed this I found it a bit of a hotchpotch. The preamble’s enough to put off newcomers to The Listener for life, and the puzzle suffers in my view from an attempt to squeeze the last drop from the theme. A couple of the associative answers, though justified by the Big Red Book, are pretty contrived and I don’t think they contribute much to the puzzle as a whole (it’s not even necessary to get the associations).The answer to 38 across is two words, not one, and I cannot justify the wordplay to 44 except by converting an abrreviation to another, related word, which I don’t regard as legitimate – it’s a bit like cluing S, which can be ‘special” as ‘particular’, though out of fairness to Hypnos it’s quite possibel that I’ve misinterpreted the wordplay.
It was easy enough to find the ‘accessory’ to highlight, but the only 5-letter alternative to the theme word that I can see in the vicinity is not indicated in Chambers as a ‘an early variant’. I shall look further to see if I can find something better.