Authorize and capture not working

I'd appreciate some input from anyone with more experience of the module. I'm trying to deduce if it is a configuration problem on my part, or the software is working as intended.

There is no call to \Stripe\Charge::create in 8.x-2.x.

The only reference to it is in uc_stripe.module, in relation to uc_recurring, but it has been commented out because it is not finished.

In fact there's a whole block of code missing from the D8 version that is in the D7 version:

//  Charge the stripe customer the amount in the order

  //--Handle transactions for $0

  // Stripe can't handle transactions < $0.50, but $0 is a common value
  // so we will just return a positive result when the amount is $0.
  if ($amount == 0) {
    $result = array(
      'success' => TRUE,
      'message' => t('Payment of $0 approved'),
      'uid' => $user->uid,
      'trans_id' => md5(uniqid(rand())),
    );
    uc_order_comment_save($order_id, $user->uid, $result['message'], 'admin');
    return $result;
  }


  // Charge the customer
  try {

    //Bail if there's no customer ID
    if (empty($stripe_customer_id)) {
      throw new Exception('No customer ID found');
    }

    // charge the Customer the amount in the order
    $charge = \Stripe\Charge::create(array(
        "amount" => $amount,
        "currency" => strtolower($order->currency),
        "customer" => $stripe_customer_id,
        "description" => t("Order #@order_id", array("@order_id" => $order_id)),
      )
    );

    $formatted_amount = $amount / 100;
    $formatted_amount = number_format($formatted_amount, 2);

    $result = array(
      'success' => TRUE,
      'message' => t('Payment of @amount processed successfully, Stripe transaction id @transaction_id.', array('@amount' => $formatted_amount, '@transaction_id' => $charge->id)),
      'comment' => t('Stripe transaction ID: @transaction_id', array('@transaction_id' => $charge->id)),
      'uid' => $user->uid,
    );

    uc_order_comment_save($order_id, $user->uid, $result['message'], 'admin');
    uc_order_comment_save($order_id, $user->uid, $result['message'], 'order', 'completed', FALSE);

    return $result;

  } catch (Exception $e) {
    $result = array(
      'success' => FALSE,
      'comment' => $e->getCode(),
      'message' => t("Stripe Charge Failed for order !order: !message", array(
        "!order" => $order_id,
        "!message" => $e->getMessage()
      )),
      'uid' => $user->uid,
      'order_id' => $order_id,
    );
    uc_order_comment_save($order_id, $user->uid, $result['message'], 'admin');
    watchdog('uc_stripe', 'Stripe charge failed for order @order, message: @message', array('@order' => $order_id, '@message' => $result['message']));

    return $result;
  }

  //  Default / Fallback procedure to fail if the above conditions aren't met

  $result = array(
    'success' => FALSE,
    'comment' => "Stripe Gateway Error",
    'message' => "Stripe Gateway Error",
    'uid' => $user->uid,
    'order_id' => $order_id,
  );

  uc_order_comment_save($order_id, $user->uid, $result['message'], 'admin');

  watchdog('uc_stripe', 'Stripe gateway error for order @order_id', array('order_id' => $order_id));

  return $result;
}

I've created a patch with the missing code, ported into D8