First I looked up global sites to understand the functionality of an SBI better. I found PowerStream (Utah) quite useful for this purpose. In Australia many RV's including my Jayco are equipped with a Redarc system. The sales brochure can be found here.
The next step up from a SBI is a complete battery management system, such as the BMPRO system supplied by Setec.
In my Jayco van both systems are utilised and that invites complications and compromises overall system functionality.