Thanks to your lead, I now have a copy of 'Mediterranean MTBs at War' and have extracted the required information. I have also been able to dig deeper and can advise the date of the incident (17 October 1944) and the indentities of the two fatalities - Able Seaman John Hinkins (MTB 397) and Ordinary Seaman Roy Young (MTB 399); the names of those wounded have not yet come to light.
Thanks again, Pioneer.
PS: Should anyone require an almost new copy of 'Mediterranean MTBs at War', I have a copy at £15.00 !!