I expect you're right, Clamzy, but I don't like ambiguities, which are very rare in The Listener. I find it difficult to believe that this one wasn't spotted.
I�ve exhausted all possibilities that I can think of to resolve the ambiguity of 33d, so I hope it is unforeseen, not an ambiguity that can be thematically resolved. Like JackDeCrow I was struck by some connections between clues and entries. For instance there�s an obvious connection between the original answer to 20 and the final entry for 38. I�ve found a number of such links, but nothing like a full set of pairings.
I�m also puzzled by the preamble�s comment: �Chambers is the sole reference, except for one proper name appearing in the grid; one further proper name referred to can be found at a related entry.�
The final grid contains one name that does not appear in Chambers (28 down); one clue answer is also a proper name that is not in Chambers, but that is altered, so doesn�t appear in the final grid. What is meant by �one further proper name referred to�at a related entry�? "Referred to" could relate to the final entry at 17, which, interestingly, relates to an altered clue answer elsewhereI took this as a hint to indicate that various entries in the final grid are in some way related, but ,as I said earlier, I haven't been able to take it to a conclusion.
I cannot make up my mind whether this is an unsatisfactory puzzle or a very clever one with some thematic trick that a lot of people are missing.