mattias@waderbook:~/test$ rm -rf *
mattias@waderbook:~/test$ mkdir A B
mattias@waderbook:~/test$ touch "A/FooBar - Title" "B/FooBar - Title"
mattias@waderbook:~/test$ find .
.
./A
./A/FooBar - Title
./B
./B/FooBar - Title
mattias@waderbook:~/test$ find . -exec rename 's/^.* - //' {} +
'./B/FooBar - Title' not renamed: 'Title' already exists
mattias@waderbook:~/test$ find .
.
./A
./B
./B/FooBar - Title
./Title
mattias@waderbook:~/test$