Crook was awarded the Distinguished Flying Cross for his actions during the battle. The official notice of this award in the London Gazette of 1 November 1940 said he had, "led his section with coolness and judgment against the enemy on many occasions. He has destroyed six of their aircraft besides damaging several more."[4]
On 8 November he was sent on an Instructor's course at the Central Flying School. He was promoted to flying officer with effect 9 December 1940.[5] In April 1944 he was posted to AFU Wheaton Aston, and in July to AFU Ternhill. He served with 41 OTU in September, then 8 (Coastal) OTU at Dyce.
Flying Spitfire IX EN662 on 18 December 1944 on a high level photographic sortie, Crook was seen to dive into the sea near Aberdeen. He was officially listed as missing in action. When collecting his belongings they found a Bible and a copy of "The Wind in the Willows" by Kenneth Grahame on his bed. A few days earlier he had celebrated his thirtieth birthday.
Crook wrote an autobiographical work about his experiences during the battle entitled Spitfire Pilot, published by Faber and Faber in 1942. A portrait of Crook by official RAF artist Captain Cuthbert Orde was reproduced on the frontispiece. Crook also wrote Pursuit of Passy, a work of fiction about an RAF pilot who crashes in France and joins the Resistance, published in 1946 by Herbert Joseph. Crook's flying log book is stored at The National Archives in Kew, and is available for public viewing.[7]
A new paperback edition of his memoir Spitfire Pilot was published by Greenhill Books in October 2021.[8][9] The new edition includes an introduction by the British historian Richard Overy, a Preface by the author's daughter Rosemary Lloyd, and an article by Air Vice-Marshal A F C Hunter, Honorary Air Commodore of the No. 609 (West Riding) Squadron.