Here is a start.
Note that a landing/assault exercise in the Slapton Sands area called FABIUS was being conducted during this time. (This was not Exercise Tiger which had occurred in April.)
This is from the "Report by the Allied Naval Commander-in-Chief, Expeditionary Force on Operation Neptune, Vol 1:
https://www.fold3.com/image/296568508
"No noticeable enemy reaction was shown to the large naval forces at sea during FABIUS. Two incidents, however, occurred in the PORTSMOUTH command patrol line."
"At 0337 in position 50 13 N., 01 27W., H.M.S. OFFA was attacked by aircraft tentatively identified as ME 210. One bomb hit the upper deck under the port after Oerlikon; another was a near miss causing splinter holes in hull. Structural damage to the ship was light. Casualties: three killed, four wounded."
"At about 0350 in position 208 (degrees) ST CATHERINES Pt., 24 miles, M.T.Bs 708 and 720 were attacked by Beaufighters. M.T.B. 708 was set on fire and subsequently sank. Casualties: four officers and seven ratings wounded."
From:
https://www.naval-history.net/xDKCas1944-05MAY.htm
Offa, bombing
ALLEN, Michael T, Petty Officer, D/JX 128409, killed
MCBRIDE, James W, Able Seaman, D/JX 171072, killed
MERRILLS, Peter R, Ordinary Seaman, D/JX 418570, killed