The early disco 1 up to around am M plate had different seat mountings.
The early ones mounted directly to the floor, where around the time they introduced electric seats they introduced some raised platforms welded to the floor.
Early disco 1 front seats are not interchangeable with later disco 1 seats.
If you have a later version (after M plate) then its possible, I don't know that, but if you have an early one then they won't fit easily.