On March 30th 1944 Dennis took part in the Nuremburg raid when Bomber Command suffered heavy losses and the rear gunner, Richard (Dick) Rogers, recalled that it was largely due to Dennis that they weathered the operation. The crew with Dennis, Mid-upper Gunner, on this operation consisted of Geoff Probert, pilot, Vic Lawrence, Wireless operator, Alan Payne, Bomb Aimer, Eric Snell, Engineer, Thomas Mackie, Navigator and Richard Rogers, Rear Gunner.

Before this crew split up their last operation was mine laying in Kiel Bay. They were hit by a JU88 and Dennis had his oxygen mask blown off his face. At one stage the tail caught alight but the fire went out, shells had also torn into the starboard main fuselage, narrowly missing the fuel tanks. Probert managed to dive and lose the fighter and they landed back safely at East Kirkby. Subsequently Geoff Probert was awarded the DFC. Richard Rogers remembers many on the squadron who were lost but the greatest blow of all was when they heard that Dennis had gone out to Wesseling and not returned.

Dennis died on Thursday 22nd June 1944, aged 20.