Pte. Allen was killed during operations at Normandy.
The No 6 Cdo War Diary for the 10th June records "Place: In the field, Le Plein a.m. - 2 Troop kill 2 snipers with 'K' gun. We are heavily mortared. We answer with our own mortars. 0800 - Enemy attacks, all troops engage. By 1700 hrs all attacks definitely repelled. Suspect enemy got it in the neck. Our own casualties total 16."