Member - Peter replied:

Bob, you can put side seats in and you can put forward facing seats in but! there will be problems.
1/ Your troopies compliance plate will state how many seats it has, any additional seating will have to be approved by an inspector and an additional compliance plate fitted otherwise you will be voiding insurance and registration.
2/ Your vehicle may not have the necessary mounts for both seat belts and the additional seats whether they are factory seats or not.
3/ I went through this problem with two 40 series troopies and the easiest way is to go to a company that has a seat design already approved and get them to fit it and you will be provided with the necessary paperwork for registration and insurance.

Peter