This extract from the Royal Air Force losses site provides details:

Date: 18th June 1940 (Tuesday)
Unit: No. 10 Squadron RAAF.
Location: Ploudaniel Brittany France
Pilot: Fl/Lt. John Napier Bell AUS162 RAAF. Age 24. Killed
Fl/Eng: Sgt. Charles William Harris AUS1730 RAAF. Age 31. Killed
Nav: Cpl.Bernard Felix Nowell 565931 RAF. Age 25. Killed
Passenger: Cptn. Norman Edward Hope 141140 Intelligence Corps. Killed

Reason For Loss:

The aircraft crossed the coast of Brittany approximately 20 Kilometres west of Carantec. It is believed that the aircraft came under either French or German fire. The aircraft was hit and the pilot attempted to land in a field near Ploudaniel but hit an embankment. The aircraft caught fire and all four occupants were killed. After the aircraft crashed some local people came from Ploudaniel and removed the bodies from the burnt our aircraft and buried them in the local cemetery before the German army occupied their town.

After General De Gaulle had arrived safely in England on Monday 17th June 1940, he made a special request to the Prime Minister Winston Churchill, asking him to rescue his family from Brittany. Prime Minister was in agreement and he informed the British Admiralty on the same day to arrange the rescue. The same day the Admiralty made arranges with the RAF to supply a Sea Plane to take a S.0.E. Admiralty passenger Cptn. Norman Hope of the Intelligence Corp was a fluent French speaker.

Cptn. Hope himself would indicate where he wished to be landed and on instructions from the Prime Minister of Great Britain would endeavour to collect General Charles De Gaulle's wife and children and bring them back to the aircraft for passage to England. The mission was considered extremely dangerous and required volunteers, the Walrus crews drew lots to see who would go. Fl/Lt. John Bell and Sgt. Charles Harris, both Australians drew the lots. The Mission: The aircraft was fully armed ready to keep defensive watch at all times. On the 18th of June 1942 they took off at 03:00 from their base at RAF Mount Batten Plymouth to carry out the mission to rescue the family of General Charles De Gaulle from France. From the time of take off nothing was heard from the aircraft. The time of the return of the aircraft depended on whether Captain Hope could find the family and also on events on the Brittany coast. The Germans were expected to approach the vicinity by 15:00 hours on the 18th. On 19th June, a Motor Torpedo Boat 29, after embarking an interpreter and a skiff, dispatched from England to the same locality, to arrive off the main channel to Morlaix at 00:01 hours on 20th June.

The skiff was to be used to land the Captain Hope, who was to endeavour to find the De Gaulle family, already having moved from the family home at Colombey Deux Eglises a month previously and were living at Carantec on the North Coast of Brittany.

The Cptn. was to convoy them to the Motor Torpedo Boat. General De Gaulle had already escaped to England on 17th of June. Captain Hope was also ordered to make enquiries regarding the missing Walrus aircraft, a description of the crew having been provided. The Motor Torpedo Boat returned on 20th June, reporting that the interpreter had landed, but found the village already occupied by the Germans.

Burial Details:

Fl/Lt. John Napier Bell. Ploudaniel Churchyard, Brittany, France. Grave 4. Son of John Henry and Eva Annie Bell Farina, South Australia.
Cpl. Bernard Felix Nowell. Ploudaniel Churchyard, Brittany, France. Grave 3. Son of Lawrence and Gertrude Nowell; husband of Susan Ann Nowell Bognor Regis, Sussex.
Sgt. Charles William Harris. Ploudaniel Churchyard, Brittany, France. Grave 2. Son of William Charles and Denah Christina Harris; husband of Joyce Florence Evelyn Harris Croydon, New South Wales, Australia.
Cptn. Norman Edward Hope. Ploudaniel Churchyard, Brittany, France. Grave 1.

Additional Information:

No. 10 Squadron, Royal Australian Air Force was the only Australian squadron to serve continuously for the duration of the Second World War in Europe. It was a coastal command squadron mainly operating Sunderland's from Pembroke and Plymouth, with 6 U-Boat kills in WW2, it also operated a number of other amphibians including the Catalina's and Walrus's. They arrived at Pembroke Dock, Pembrokeshire on 3rd September 1939 and trained under RAAF Command. On 10th October 1940 they were placed under Coastal Command Control, for European War Operations. Then to Mount Batten, Plymouth, Devon on 1st April 1940.

Thanks to Victor Smith for information supplied.