I quote" No {separate} SPD's present on DC installation. Inverter data sheet show some over voltage protection but no detail. Member to investigate protections in place with inverter manufacturer and their suitability /adequacy for the installation. Alternatively add further SPD's to the installation and evidence to NAPIT for review"
It was a 3.68kwh GEN3 inverter!
One for Giv support to answer formally but you may just be better off fitting an SPD and being done with it to save waiting. I'm not aware of any document available publicly. IEC 62109-1 -2 which from memory covers this (and the datasheets do mention this even on Gen 3) but whether that would be enough I don't know - I doubt Giv would hand those over as they are very useful for reverse engineering.
I do know that my Gen 1 Hybrid has a varistor across its inputs, I doubt they've made it worse for Gen 3?
Example Solar Edge conforming to 62109 which talks about surge protection: https://knowledge-center.solaredge.com/sites/kc/files/lightning_surge_protection.pdf
Amusingly (or not) The RS485 interface in the Gen1 hybrid (and possible later, don't know) Doesn't have surge/over voltage protection even though the pcb has locations for it. Bottom most pcb in the photo.