In a previous update we switched to automatically sorting group members by surname, but a few users preferred the old way of sorting members (based on the entire name), so MailShot 5.1 allows you to choose a few options.
To show the field used for sorting (Typically “lastname, firstname”) enable “Show Surname First” on the MailShot page in Settings.
To sort on full name instead, enable “Sort On Full Name” on the MailShot page of the Settings app.