Display the return to event cart button before the SPCO content.

tw_display_return_to_event_list_beginning_spco.php

<?php // Please do not include the opening PHP tag if you already have one.

add_filter('FHEE__registration_page_wrapper_template__display_time_limit', 'tw_display_return_to_event_list_beginning_spco');
function tw_display_return_to_event_list_beginning_spco($value){
    $checkout = EE_Registry::instance()->SSN->checkout();
    if ( $checkout instanceof EE_Checkout ) {
        // returning to SPCO ?
        if ( $checkout->revisit ) {
            // no return to cart button for you!
            return $value;
        }
        // and if a payment has already been made and this isn't a revisit
        if ( $checkout->transaction instanceof EE_Transaction && EE_Registry::instance()->REQ->get( 'e_reg_url_link', '' ) === '' ) {
            $last_payment = $checkout->transaction->last_payment();
            if ( $last_payment instanceof EE_Payment && $last_payment->status() !== EEM_Payment::status_id_failed && $checkout->transaction->paid() > 0 ) {
                return $value;
            }
        }
        // Build and echo the return to cart button
        $html = '<a class="return-to-event-cart-mini-cart-lnk mini-cart-view-cart-lnk view-cart-lnk mini-cart-button hide-me-after-successful-payment-js button" href = "' . add_query_arg(
                array( 'event_cart' => 'view' ), EE_EVENT_QUEUE_BASE_URL ) . '" ><span class="dashicons
                dashicons-cart" ></span >' . apply_filters(
                'FHEE__EED_Multi_Event_Registration__view_event_cart_btn_txt', sprintf( __( 'return to %s',
                'event_espresso' ), EED_Multi_Event_Registration::$event_cart_name ) )  . '</a >';
        echo $html;
        // Remove the original return to cart button.
        remove_filter(
            'FHEE__EE_SPCO_Reg_Step__reg_step_submit_button__sbmt_btn_html',
            array(  'EED_Multi_Event_Registration', 'return_to_event_cart_button' )
        );
    }
    
    return $value;
}