For as long as I can remember I've used Mutt in an ssh session as my favourite mail client. It's quick, fast and accessible from anywhere that I can get a shell session. I've always had a problem with the display when I'm running under GNU Screen in that the display corrupts when spurious characters appear in subject lines. I've experimented with different term settings but to no avail. I think that I've now cracked it thanks to this article:
I've been trying to fix the issue on the command line. Instead I should have been looking at the outer shell; setting the character set translation to UTF8 in putty has made everything look beautiful. Thanks Steven Haigh netwiz at crc.id.au!