I have similar concerns to David following my purchase of a Sony Vaio battery replacement.
It was shown on their website as a genuine Sony item but the battery I received was not Sony branded and in addition came with a small CD with Chinese (?) writing on it. I emailed salesbattery to ask them to explain both of these and the lack of warning when I ordered. No answer to date but I am chasing.
If you check the Amazon site you will see a fantastic service and customer approval record......something suspicious here??