Hi Trex, I believe that if the battery is "packed with" and not "installed" in the bike the whole carton must be certified, which would cost a fortune and is unpractical. You cannot send a bike with a battery installed if a second "spare" battery is in the same carton it has to be sent as class 9 DG.
If a battery is sent installed in a bike the bike does not have to be sent as class 9 DG. However the battery itself still must be certified.
Another new one to me.... if a business imports more than 333kg of batteries, whether installed in a bike or not, the company must employ a DGSA as a consultant. In most cases that is less than 100 bikes.
All the best
David