In the UK any new electrical circuit, which includes an EV charger, solar DC/AC inverter, cooker or lighting circuit etc is notifiable work and must be completed by a part P registered professional.

It doesn't matter if it's a self install of an inverter that can be zero rated for export, if the house consumer unit is connected to the national grid you can't self install (unless you are a registered professional as stated). Essentially to connect solar panels to a house that is also connected to the grid will always have to use a grid tied inverter.

Only way to use an off grid inverter, which is what you described, is if the house is entirely off grid (and therefore has it's own earth which is another point but not really worth going into). The description of an off grid inverter you use would not be the definition used in the UK in relation to building regs (it would be a grid tied system because it is connected to the grid, pass through is irrelevant).