Is it possible to retrieve the submitter email address? I have sent out a survey, but unfortunately I haven't set a name/email field, and I cannot see

Unfortunately no. Since you did not include in the form an Email field, there will be no other way to find out or get the email address of the respondent.

Please add the Email field on your form now so that you will be able to get the required data on incoming submissions.

Let us know if you need further assistance.