Access Individual Fields - Contact Form - Swiftmailer
This definitely isn't a very nice solution, but it does "work".

I created a module, and added this into the .module file.

function modulename_mail_alter(&amp;$message)
{
  if(empty($message['params']['contact_message'])) {
    return false;
  }

  //$message['body'][1] = str_replace("\n\n\n\n",'',$message['body'][1]);
  //$message['body'][1] = str_replace('   ','',$message['body'][1]);
  $contactMessage = $message['params']['contact_message'];

  // Build message body
  //$message['body'][0] = [];
  $message['body'][1] = [];
  $message['body'][1] = "&lt;br&gt;&lt;br&gt;";

  if($contactMessage-&gt;hasfield('field_your_name')) {
    $message['body'][1] .= "&lt;br&gt;&lt;br&gt;Full Name:&lt;br&gt;";
    $message['body'][1] .= $contactMessage-&gt;get('field_your_name')-&gt;getString() . "&lt;br&gt;&lt;br&gt;";    
  }

  if($contactMessage-&gt;hasField('field_email_address')) {
    $message['body'][1] .= "Email Address:&lt;br&gt;";
    $message['body'][1] .= $contactMessage-&gt;get('field_email_address')-&gt;getString() . "&lt;br&gt;&lt;br&gt;";
  }

  if($contactMessage-&gt;hasField('field_telephone')) {
    $message['body'][1] .= "Telephone:&lt;br&gt;";
    $message['body'][1] .= $contactMessage-&gt;get('field_telephone')-&gt;getString() . "&lt;br&gt;&lt;br&gt;";
  }

  if($contactMessage-&gt;hasField('field_mobile')) {
    $message['body'][1] .= "Mobile:&lt;br&gt;";
    $message['body'][1] .= $contactMessage-&gt;get('field_mobile')-&gt;getString() . "&lt;br&gt;&lt;br&gt;";
  }

  if($contactMessage-&gt;hasField('field_company')) {
    $message['body'][1] .= "Company:&lt;br&gt;";
    $message['body'][1] .= $contactMessage-&gt;get('field_company')-&gt;getString() . "&lt;br&gt;&lt;br&gt;";
  }

  if($contactMessage-&gt;hasField('field_enquiry_type')) {
    $message['body'][1] .= "Enquiry Type:&lt;br&gt;";
    $message['body'][1] .= $contactMessage-&gt;get('field_enquiry_type')-&gt;getString() . "&lt;br&gt;&lt;br&gt;";
  }

  if($contactMessage-&gt;hasField('field_version')) {
    $message['body'][1] .= "Version:&lt;br&gt;";
    $message['body'][1] .= $contactMessage-&gt;get('field_version')-&gt;getString() . "&lt;br&gt;&lt;br&gt;";
  }  

  if($contactMessage-&gt;hasField('message')) {
    $message['body'][1] .= "Message:&lt;br&gt;";
    $message['body'][1] .= $contactMessage-&gt;get('message')-&gt;getString() . "&lt;br&gt;&lt;br&gt;";
  }  
}


So basically I clear the message, and then build it up again...