Hi
Think it was 175 Sq, escorted by 118, 66 & 501 Sq's, not sure, but don't think there were any RAF losses.
cheers
Jerry
extra info
source
http://www.nzetc.org/tm/scholarly/tei-WH2-1RAF-c16.html
The attacks on ports and shipping had already produced good results. Squadron Leader Malfroy had led his No. 66 Squadron in a typical mission on 15 May against a convoy off the Brittany coast. Malfroy led the attack from sea level and his Spitfires raked the ships with cannon fire. Hurri-bombers from No. 175 Squadron then followed them in and one ship burst into flames, two direct hits being seen amidships on another vessel which blew up and sank almost immediately.