Guess what? Seat question!

Dear lads and ladies,

I've been investigating putting a bench seat in the back of my 2007 puma 90 hard top so I can carry humans in the back... Now I have searched but it seems quite complex with a lot of legislation changes. So I was wondering,

can I put a side facing bench seat in the back with/without seatbelts and drive? I checked my V5 and for some reason it lists the car as a 4 seater, so I assume I'm good legally to carry folks in the back, but are the sidefacers illegal now thanks to the EU?

I assume I'm also allowed to technically carry 2 unfastened loose people in the back since it's written down as having 4 seats? I seem to remember police on TV saying passengers have to wear a seatbelt "if there is one available for them to wear", is this right?


Thanks

I thought that was only if the vehicle was over a certain age and to the spec of the original vehicle. ie if the original was unbelted seats ok.