Hi Nigel, I have a 2002 Jazz also. It doesn't have a switch to turn off the passenger airbag.
I'm not sure how legal/safe it is to fit your own switch, but i personally wouldn't try.
If an airbag is disconnected, the airbag module will know and throw a light up on the dash. You can get round this by disconnecting the battery, removing the airbag and fitting a 2ohm resistor in its place, but this isn't a viable option if you want to do this regularly.
Is your query because you want to fit a baby carrier in the front? If so, there is a sticker on the windscreen telling you not to do that.
Steve.