The generated PDF discharge letter always picks the 'email' transport by default. This means users expecting to define a 'print' version of the discharge notice get confgused and/or wrong results. This was highlighted by bug 14251, which fixed styling the PDF with CSS, which is only picked if the 'email' transport letter is used. It is trivial to see this doesn't work as no transport is passed to GetPreparedLetter, which then defaults to 'email'.