Thanks for the responses, really appreciate this discussion.
Somehow to me (in my admittedly absolute ignorance) the installation of a change-over switch sounds like an an unnecessary overkill considering the switchover capabilities of the Invertors. I am worried about adding potential redundancies into a system unless entirely necessary/required. I want to mitigate risks in the system as I will be away for extended periods (ha ha especially after this "house arrest" we are all having to endure, the bush is calling me). I will check if required for COC requirements.
A further question if I may....... DC fuse as well as DC breaker ??? Do I need both, does the fuse add a layer of protection (or visa versa) that the breaker doesn't? Once again just want to be risk averse and do not want to add "unnecessary" potential failure points unless absolutely required.
Stay safe and healthy