Last of the translation. Thanks for sticking with me! If the J Wiki article information is not available in English, here is my translation of their Japanese paragraph above:
"In the 20 June 1943 bombing of Port Darwin, though they were escorted by type 1 Oscars, 16 of these 18 (Helen) heavy bombers which had set out made it back despite the attack of 46 Spitfires. For this reason when combined with the correct fighter escort, they were highly evaluated, both for their defensive firepower and for their bomb loads. In actual fact upon return the majority were so heavily damaged that they were unrepairable and had to be destroyed, so this was the one and only time they were ever used against Port Darwin."
J Wiki, translation, jolihokistix, 6 May 2017