Can We Move On, page-172

All of the insto accounts you mention are nominee accounts so they are only there in their capacity as custodian for the actual owner(s). The actual owners can be overseas buyers or local buyers who don't want their name on the register.
The SMS holding was held in a National nominee account for a while but it looks like they, maybe with TNG, decided earlier in the year that they'd like their name on the register.

from Mr Google

"A nominee share holder refers to a company member holding the shares on behalf of the actual owner or beneficial owner. S/he is the registered owner of the share. A nominee share holder holds the share under a custodial agreement."