src/Tasks/ShopMigrationTask.php
public function migrateMemberFields($order)
    {
        if ($member = $order->Member()) {
            $fieldstocopy = array(
                'FirstName',
                'Surname',
                'Email',
                'Address',
                'AddressLine2',
                'City',
                'Country',
                'HomePhone',
                'MobilePhone',
                'Notes',
            );
            foreach ($fieldstocopy as $field) {
                if (!$order->$field) {
                    $order->$field = $member->$field;
                }
            }
        }
    }
public function migrateMemberFields($order)
    {
        if ($member = $order->Member()) {
            $fieldstocopy = array(
                'FirstName',
                'Surname',
                'Email',
                'Address',
                'AddressLine2',
                'City',
                'Country',
                'HomePhone',
                'MobilePhone',
                'Notes',
            );
            foreach ($fieldstocopy as $field) {
                if (!$order->$field) {
                    $order->$field = $member->$field;
                }
            }
        }
    }
Customer and shipping details have been added to Order,
so that memberless (guest) orders can be placed.