Information on Sadler's death from Australian RAAF records, as a result of RAAF personnel serving on attachment in the RAF. Note this was yet another flight carrying "wireless investigation equipment":
NAA : A705, 163/93/462.
Aircraft Type: Wellington
Serial number: X 9913
Radio call sign: ZP -
Unit: 109 Sqn RAF
Summary:
Wellington X 9913 of 109 Sqn RAF took off from RAF Stradishall at 1950 hours on 28 March 1942 to carry out a special duty flight for the Air Ministry. The route was from base to a point 60 miles north of Terschelling, and then coastwise at a range of 60 miles along the Friesian Islands, the west coast of Germany and the west coast of Denmark to Skagen. The return trip was on a parallel track but at a distance of 30 miles from the coast. The aircraft had fuel for 15 hours, and was installed with special wireless investigation equipment and carried 2 special equipment operators to work the equipment. Nothing was heard from the aircraft after take off and it did not return to base. The route was close to enemy fighter zones and it may have been intercepted.
Crew:
RAF PO Maygothling G.J., Captain (Pilot).
RAAF 404933 Sgt F.J.Cassells, 2nd Pilot.
RCAF PO Convey, L.J., Observer.
RAF PO Cussen, R.J., Wireless Operator//Air Gunner.
RAAF 404478 Sgt F.G.Bower, Wireless Operator/Air Gunner.
RAF Sgt R.A.Walker, Air Gunner.
RAF PO Sadler, B.E.P., Special Equipment Operator.
RAF LAC R.Rendell, Special Equipment Operator.
...
In Memory of
Pilot Officer
Basil Elgar Percy Sadler
67252, 109 Sqdn., Royal Air Force
who died on 28 March 1942 Age 24
Son of Walter Percy and Edith Hilda Sadler, of Wandsworth Common, London.
Remembered with Honour
Runnymede Memorial