Hi,
Very often if you know the name of the journalist, you can 'guess' the email address. For example the name of the journalist is Joe Bloggs @ sunday times, I would guess the email address to be
joe.bloggs@sunday-times.co.uk or
joe_bloggs@sunday-times.co.uk
If you do get the email address wrong, you should receive a notification so you can make some further guesses then.
Hope this helps.