You didn't have to learn standard masses. The CAA have said they won't get asked in the UK exams until the tables themselves are included in the CAP, they feel its unfair to ask you to memorise something that would ordinarily be in the books. The only related question I can think of asks you when standard masses for baggage can be used.
The JAR specimen paper has a question in it about the standard mass used for children, it also has your trim sheet question in it. The answer was 46130kg and 17.8% so it sounds like you got it right.