Leasure Battery

Hi Has member  fitted a second leasure battery on a A/S Bourton? If  so could they pass on any information on how and where to fit it.
Thanks

Does your van have solar, if so, what size (80w, 100w, more..)?

These are under the cab passenger seat in a 2017 Bourton:

Thank you for the reply's sorry for the delay I have been away. Yes my van has a solar panel not sure what size though. Also the standard measure battery is is under the passenger seat. so no room for another one there.

I didn't create the picture of two batteries under the passenger seat with photoshop, it is a picture of an actual installation in a 2017 Bourton.

Thanks for that, so it looks like there is room for 2 mounted sideways I will have a measure up