Looking to output perch_content_custom into a PHP variable

Basically what I am trying to achieve is to output a single field into a PHP variable for later use within an emailed form. It is an event booking form and I want to output the events name within the emailed form.

Here is the current code I am using to try and get the field into the $event_name variable:

$event_name = perch_content_custom('Event', array(
                              'page' => '/events/event.php',
                              'template' => 'eventname.html',
                              'filter' => 'slug',
                              'match' => 'eq',
                              'value' => perch_get('s'),
                              'skip-template' => 'true',
                              'return-html' => 'true',
                            ));

The eventname.html simply contains the below, so I can pull a single field from the larger main template:

<perch:content id="eventName" type="text" />

I have been trying to get this working for a while now but to no avail. Currently when I receive the outputted email all I receive is the word "Array" instead of the templates content.

Any help would be brilliant, I am not massively familiar with PHP.