Riki . . . I have changed a couple of sets of MV6 seats for Elite ones & there is a problem that occurs with the yellow connector on passenger side . This is only used on Elites for the "child seat " facility & should not be plugged in when putting Elite seats into other models AFAIK.
On both the MV6's I have put Elite seats into this yellow connctor block was just taped up below the seat . The first one I changed I connected this yellow block connector & the airbag light came on . . . second one I did I left it unconnected & all is ok Presume it will be the same on the GLS or any other model bar the Elite.
But in my cases I was swapping FL into FL not sure that is the case with yours or the yellow connector will even be laying below the seat on the GLS .Hope this makes sense & may help
EDIT: I think RobG did post up a picture of this yellow connector . . . but had a quick look & could not find it