That won't work, because the variable that will be passed via a <FORM> tab will be the name inside the <SELECT> statement.
so if the code is echo "<SELECT name = 'postcode'>The option tag has to make sure that the value is both the postcode_in and postcode_out variables (which I have done), so when the form variable is passed, it will be the name in the <SELECT> statement.
so I have to someone state on the next page that the variable $postcode is in fact two variables from the database, and I only need information that is extracted from both the postcode_in and postcode_out together
a flowchart to explain
Page1.php
select from db postcode_in and postcode_out variables, put them together as a variable called $postcode which will be passed to page 2 via a Form
Page2.php
seperate the $postcode variable so that the $postcode_in and $postcode_out variables reappear, which then are used to display the rest of the information from the db.