Hello Jan-Olof,

Recent books by the USMM (Turrini and Miozzi) or by Giorgerini have followed the British correction (since 1988) that TRIAD was the submarine sunk by ENRICO TOTI.
RAINBOW is believed to have been rammed and sunk by the steamer ANTONIETTA COSTA on 4 October 1940.
The wreck of HMS TRIAD may have been found off C. Colonne but I am not sure.
The site [www.sportesport.it] lists her as one of the wrecks off Southern Italy but I do not know if it was actually located.
About 24 hours before the ENRICO TOTI action, the submarine SANTORRE SANTAROSA reported also attacked by a submarine but I do not know the actual position, this could well have been TRIAD or RAINBOW (then the A. COSTA incident could be also put in doubt).

Best regards,

Platon