Tourneo Inurance/Seat Problem.

[valvorado]

son brought a 07 tourneo abot 2 years ago - it was ex police, 5 seats + a cage in the back - he uses it for transporting the dogs.
he tried to sell it yesterday but the guy came back & said it was too expensive (about £800) because it was an 8 seater.
i checked the v5 & it is an 8 seater.

does anyone know if it;s just a simple matter of changing the v5 & notifying the dvla or is there another rigmarole involved?