Merge forwardport of #12227 to 2.3-develop branch

Applied pull request patch https://github.com/magento/magento2/pull/12227.patch (created by @andrew-garside-temando) based on commit(s):
  1. 149268c

Author: magento-engcom-team

dev/tests/api-functional/testsuite/Magento/Sales/Service/V1/OrderCreateTest.php

@@ -140,7 +140,7 @@ protected function prepareOrder()
                 [
                     'shipping' => [
                         'address' => $address,
-                        'method' => 'Flat Rate - Fixed'
+                        'method' => 'flatrate_flatrate'
                     ],
                     'items' => [$orderItem->getData()],
                     'stock_id' => null,
@@ -232,6 +232,9 @@ public function testOrderCreate()
         $this->assertEquals($order['grand_total'], $model->getGrandTotal());
         $this->assertNotNull($model->getShippingAddress());
         $this->assertTrue((bool)$model->getShippingAddress()->getId());
-        $this->assertEquals('Flat Rate - Fixed', $model->getShippingMethod());
+        $this->assertEquals('Flat Rate - Fixed', $model->getShippingDescription());
+        $shippingMethod = $model->getShippingMethod(true);
+        $this->assertEquals('flatrate', $shippingMethod['carrier_code']);
+        $this->assertEquals('flatrate', $shippingMethod['method']);
     }
 }