19a Novel by Michael Frayn, author of Towards the End of the Morning , Headlong and the play Copenhagen (5) S?I?S Is it Spies or Skios? Both fit and both were written by him. The clue doesn't give the date of publication. I suppose both are right and will be marked as such.
Thank you. I would imagine that insufficient information was the problem with the crossword setter who didn't perhaps realise that two titles would fit the clue.