adone

Hi everyone,
Last year, after numerous power outages in my area I decided to go fully (more or less) off grid. I have an existing system (3kw RCT vmII, 2.8kw Hubble battery) that covers some stuff, but not enough to carry on normally during an area outage. That runs on a completely separate grid to the house mains. I'll be leaving that in place until the batteries or inverter dies.
The new system is 2 x Solis S6 pro 6KW inverters paralleled for 12KW output. 12 x 550w Jinko solar panels, split in 2 strings to maximise morning and afternoon sun. The roof gets partially shaded by the neighbours tree in the morning and councils tree on the pavement in the afternoon. 3 x Dyness BX51100 batteries, rated at 0.5C. I may add to these depending on how my usage goes in winter. I'm not looking to feed back to the grid, I don't even think it's a possibility in my municipality yet, so I plan to run the system in islanding mode most of the time. I'm not splitting my load into essential vs non essential. I want everything to run as essential so I'm thinking of just using my existing DB. I've attached a basic plan of my wiring. I just want to check if I'm missing something. The existing DB is in my passage, so the inverter an batteries are installed in another room a couple meters away. I'm not sure if I should have an addition mini DB to cut off power to the inverter at the inverter or if the initial circuit breaker at the passage DB is enough. I was told that the inverters have isolation for the PV so I don't need an additional one for that. Is that true or should I also have an Isolator for each solar string? 
So the plan is to take the Eskom mains out of the existing DB and move it into a smaller DB that contains a breaker for the inverter and then goes to a changeover switch on another board to divert power from mains or the inverter. Am I creating too many sub boards? 
Also, if I have a surge arrestor coming in at the Eskom mains, and one at the inverter output, should I put another one at the existing DB input? Or is that creating too many routes? 
Grateful for any advice you've got.