They look like 4-point harnesses but sharing one mount behind the seat. Scrutineers don't like this but I am not sure the Blue Book states, as a roadgoing car some may say one (3 point) is allowable. It becomes very questionable ground if the harness is a 4 point harness.
Bottom line is what is safest in the interest of the driver and it goes in the following sequence... 6 point; 5 point; 4 point; 3 point.
Blue Book - Section K 2.1
Seats, Seat Belts and Headrests
2.1. All seat safety belts must be complete units sourced from a recognised manufacturer and fitted in accordance with the manufacturers’ instructions, MSA recommendations or FIA requirements. (See Drawing Nos. 39, 40, 41, 42 and 44.) Where the vehicle manufacturer’s standard safety belts and associated fitments are not utilised, bolts must be of a minimum 7/16in UNF or M12 (grade 8.8).
2.1.1. Three point. One diagonal shoulder strap and one lap strap, with three anchorage points on the chassis/body shell or roll over bar of the vehicle on either side and to the rear of the driver’s seat.
2.1.2. Four point. Two shoulder straps and one lap strap, with four anchorage points on the chassis/body shell or roll over bar of the vehicle, one either side of the driver and two to the rear of the driver’s seat.
2.1.3. Five point. Two shoulder straps, one lap strap and one strap between the legs with five anchorage points on the chassis/body shell or roll over bar of the vehicle, one either side of the driver, two to the rear of the driver’s seat and one between the legs.
2.1.4. Six Point. Two shoulder straps, one lap strap and two straps between the legs, with six anchorage points on the chassis/body shell or roll over bar of the vehicle, one either side of the driver, two to the rear of the driver’s seat and two between the legs.