Hi Anthony & welcome to the forum.
I presume the seats are the type which fold away into the floor, leaving a flat floor/luggage area.
If so, I would consider them to be “occasional seats” which do not require seat belts. The car can be presented for test with the seats folded away, and with the seat belts removed.
Here is a copy & paste extract from the MOT Manual
Seat belts aren’t needed for:
seats that are only used when the vehicle is stationary, such as a sofa in the living area of a motor caravan
side facing seats
occasional seats that fold down when not in use
😀
