rover 75 passenger airbag?

hi i have bought a 1999 rover 75 and the airbag on the passengers side has been disconected because one of the other owners had a child sit fitted. how do i reconect the airbag? i have looked under the sit and found no wires disconected. the fuses are in place aswell. i think maybe the wire to the airbag has beed disconected if so how easy is it to take out the airbag and reconect. or is there a on/off switch somewhere.