Clues in the crossword!

I've managed to finish the Guardian's prize crossword from last Saturday, with the exception of one word, and discovered that, amazingly, there are subliminal clues to the fact that today is my 300th blip. First, the crossword is based around two composers, of whom several works feature in the answers; one was born 200 years ago, the other died 50 years ago, but since the second is twice as fun as the first, you have to count his anniversary twice. That's 300. Second, when the first word of the first clue is looked at under a microscope, it will be observed it is actually the number 300, as you can see from my analytical macro study of the clue. What more proof do you need?

Please also note that since the deadline for submittal for the prize crossword has not yet arrived, DO NOT RELY ON THOSE ANSWERS YOU CAN SEE AS BEING CORRECT (even though they are), and use them as a cheat in submitting your own solution, because you won't win (nobody ever does, I believe) and the prize isn't worth having anyway.