Multiple instances of same form in views do not work properly
After looking for a while on the Internet, I found a solution. 

Firstly, you can add a '#name' to your submit buttons to distinguish them, and then do a switch case in the submit handler... I was trying this for a while before realising that it was not my problem.

My problem consists in the fact that I am calling the same form multiple times on the same page. I found a previous post which highlighted the fact that each form should get a unique form_id in order for it to work. Using hook_forms was the best method for this. I followed the instructions from here. It worked despite it being for Drupal 6.

Amended code...
I added this hook:

function mymodule_forms($form_id,$args){
  //Check if the form_id passed to drupal_get_form() contains the string 'mymodule_form'
  if (strpos($form_id, 'mymodule_form') !== FALSE) {
     //Lets attach mymodule_form to $forms[$form_id].  This effectively allows you to use the same form builder function to build a form with any form_id of your choice.
     $forms[$form_id] = array(
       'callback' =&gt; 'mymodule_form',
     );
     return $forms;
  }
 }


And then, the code that calls the form was amended to this:

function mymodule_answers($nodeid) {
   $theform3 = drupal_get_form('mymodule_form_'.$nodeid,$nodeid);;
   $output .= '&lt;p class="text-center over"&gt;'.drupal_render($theform3).'&lt;/p&gt;';

   return $output;
}


Voila!