I did a quick analysis of the situation in the Bay of Biscay on 1/2 August 1943. There were four groups of two U-boats each passing outbound through the Musketry/Seaslug area:
U-454 and U-706 had left La Pallice on 26 July
U-129 and U-525 had left Lorient on 27 July
U-106 and U-107 had left Lorient on 28 July
U-218 and U-383 had left Brest on 29 July

Allied aircraft operating in the area on the dates in question reported the following attacks, all can be attributed to certain U-boats from corresponding German reports:
01/1442 Sunderland (B/10 RAAF) > sank U-454
01/2013 Sunderland (V/228 RAF) > sank U-383
01/2147 Liberator (K/59 RAF) > attacked U-106
02/0907 Hampden (A/415 RCAF) > sank U-706
02/0920 Liberator (T/4 USAAF) > sank U-706
02/0932 Wellington (C/407 RCAF) > damaged U-106
02/1520 Wellington (B/547 RAF) > damaged U-218
02/2016 Sunderland (M/461 RAAF) > sank U-106
02/2020 Sunderland (N/228 RAF) > sank U-106

The attack carried out by Liberator K/59 was made in 46.44N/11.26W and assessed as "U-boat present, no damage" by the Admiralty because the depth charges dropped undershot. According to the survivors of U-106 this attack in BE6695 did indeed no damage, but strafing killed one crew member and wounded two others. The attack of Wellington C/407 the next morning forced U-106 to return to port with only a limited ability to dive, so the U-boat had to remain on the surface when discovered by two Sunderlands in the evening and was subsequently sunk.

Best regards
Rainer

Crew member of uboat.net