Would I get away with this?

[sharpener]

Am now planning a different installation. Smaller house and roof unsuitable for panels so am thinking of a bog-standard 16A battery/inverter system.

Water is heated by gas so immersion is for emergencies only.
Cooker and washer/dryer are on separate circtuits anyway.

I think everything else would run OK off a 16A supply (lights, TV, computers, alarms etc)
Limitation: cannot run kettle, microwave and toaster all at the same time!

Would fit a changeover relay so all the above would switch automatically to grid if inverter fails, or manually if required.

So I know I could do this with a Victron MultiPlus 3000 (and this has a 32A passthrough rating which is certainly adequate).
Can any of the cheaper Chinese hybrid inverters be operated like this i.e. using the EPS/UPS output all the time?

And which of them did we decide was fully compliant with UK earthing requirements in island mode?

TIA