Sorry for double images - struggling with the tech, to revisit the inverter question I am assuming this is it, if so found it under the passenger front seat, what if any of this is preparation for a second battery ?
The space is limited under the seat because it is a life variant, A caddy Maxi van has no back seats and has a void under the floor where the back passengers feet would go that is big enough for 2x 110Ah leisure batteries, a charger, a dc to dc converter and a 3KW Pure sine wave inverter, and still store the tyre change tools.
Do the Caddy front seats spin? We had the Zoom adaption fitted and it is brilliant