SPD location in off grid setup

I have an off grid victron system, but i also need to use the grid to charge the batteries and I also have a manual changeover switch in my DB, this changes between inverter power and grid power. I have a SPD, and im asking where it should be connected to, the grid side or the load side of the changeover switch? Currently it's connected to the grid side, as I'm still in the process of wiring the board.

I have an off grid victron system, but i also need to use the grid to charge the batteries and I also have a manual changeover switch in my DB, this changes between inverter power and grid power. I have a SPD, and im asking where it should be connected to, the grid side or the load side of the changeover switch? Currently it's connected to the grid side, as I'm still in the process of wiring the board.