I enjoyed this enormously, though I agree that the clues generated from extra words had some pretty damn obscure references. This puzzle shows my age - the last answer to the generated clues didn't exist when I studied the subject at university!
Does anyone else agree that there is an ambiguity regarding the extra word for 25 across? There are two possibilities which both give the same single letter abbreviation, though it doesn't really matter generated clue as either works equally well.