Further update on the Quattro, the above was not a solution and I was advised to remove all assistants as I variously had the Quattro stop charging and stop inverting at one point with SoC around 60% so neither low nor high.
With DVCC off and all assistants remove (pretty concerning running without BMS two wire link) the system charged up and discharged when power was removed. So wired the generator start stop to the temp input and added an assistant to trigger ignore AC 2 in plus two signal BMS and all was well. Then created a Node Red flow to switch the Relay 2 on the Cerbo based on SoC and load and although this may need refining, all seems well so far, no shut downs. 