We are given examples like this
in BS 7671, and it does seem a 30 mA RCD is recommended which makes sense when you consider your in a metal box, unless you are exporting the supply from the inverter to items outside the metal box, then no real need for an earth, just bonding.
I used an inverter in a narrow boat, and the shore supply went to a class II battery charger, so shore earth was not imported, but it does depend on how the batteries are charged. Look at electric cars and we see the problem with earthing. Why the electric car is not class II not a clue.
But if we look at a tooth brush supply, we consider it safe with a TT as only one item can be plugged in, and the same applies to an inverter, with an inverter supply to one item there is no real need for a RCD or earth system, in fact it can make it more dangerous not less, but with multiple low voltage items (230 volt) type 1 used at the same time one may develop a line 1 to earth fault and another line 2 to earth fault so you can have 230 volt touching two items, so we bond and line 2 becomes a neutral.
So to quote
The following monitoring devices and protective devices may be used:
(i) Insulation monitoring devices (IMD's)
(ii) Residual current monitoring devices (RCM's)
(iii) Insulation fault location systems
(iv) Over current protective devices
(v) RCD's
and the designer has to decide which is the most appropriate method. To be frank with a bank of class II battery chargers I would not be worried if non were used, but once you start using class I then you have to assess the risk and select the appropriate method, and to do that remotely is not really the way to do it.
I have been approached at work far too many times by some one asking advice, and too many times after I have visited them and realised they had not really told me what they were doing and my advice was wrong as a result. So would say get some one to actually look at what you are doing.