Bongo Fury

Just brought a rear passenger side flip up seat the holes are on the wheel wells is it straightforward to fit would it be an mot failure if no seat belt really would appreciate some advice

Mechanical diagrams with all the parts here https://www.lushprojects.com/bongoparts ... tr.html#12 two pages listed for them.
A third page covers the seatbelts https://www.lushprojects.com/bongoparts ... mgno=.html

Thanks so much