WELCOME ABOARD!
Evading destroyers is always a tricky question, especially if there are more than one. Silent running is your friend, until you can hear their propellers without the hydrophones. If they're that close then they are about to drop. Go to flank speed, chance course and depth as quickly as possible, since depth charges once dropped can't change their settings.
A note about your sig: The King at the time was George VI. "Her" Majesty wasn't queen until seven years after the war ended.
