2. The two people in question are school headmistresses who will be writing to each other regularly - would they be more likely to use airmail or surface mail? My first thought was that airmail wouldn't be generally available, but Wikipedia informs me I was wrong about that - would it be too expensive, though?
(Yes, this is Chalet School fanfiction!)
I've tried Googling things along the lines of "mail between UK/England and Europe 1940s/1950s", "mail delay 1940s/1950s", and so on, with no useful results. I looked at the Royal Mail site, which quotes expected delivery times for Western Europe as 2 weeks for surface mail and 3 working days for airmail, but I've no idea how to extrapolate that back - or even how accurate it is for today!
Thanks in advance :)