It had been about a year since Eustace was there for VDT, right? So probably the Pevensies were all still in school, just as he was. Peter had been studying for exams the year before, so perhaps he was already in university. We know Susan wasn't one for studies, so she might have been ... what did young ladies do after WW II? Me mum got a job while she was in high school serving ice cream sodas, and right after high school went to work in a factory, I think. So Susan was probaly finishing high school and going ont dates and thinking about some kind of job ... Edmund and Lucy would still be in school.