There seems to be a new problem: the attack by 22 Sqdn. and 815 Sqdn. on Waalhaven could have taken place in the evening of 11/05/1940, instead of 12/05/1940. No mentioning of an attack in the evening of 12/05/1940 in German sources, according to one of the makers of
War over Holland.
Swordfish L9784 was probably hit by German light flak, based on Waalhaven airfield. Either flown in or captured Dutch 20 mm guns.