The plan was to at some point to change the front bench and drivers seats in the Vito into two single seats that could swivel round to face the inside of the van when not in transit. Given that swivel plates are around £100+ each, and you’d need another driver seat and base to install on the passenger side, it’s worth considering the option of buying a set of seats from a Renault Espace from a vehicle dismantlers, using two or three of the rear seats as removable rear passenger seats. On Gumtree you can find a set of 7 seats for £50. The seats for the Harvebago front are from an Espace, with faux- leather covers.
The proposed layout would see the kitchen units move to the rear, and be removable – either on a fixed frame and stand, or as a free=standing unit, but would most likely inhibit the ability to cook within the van.
Developing on this and the outdoor kitchen concept that was in mind, it would also be feasible to create a more modular seating system, allowing more seating configurations, storage, and the ability for utilities to be used both in and outside the vehicle (click images to enlarge):