Does anyone know how to turn the passenger air bag off, on my 1999 T octy estate?

the only way to de-activate it is thorugh the glove box, if there is a key operated switch you can turn it off. if its not there then not turny offy

You should go to the dealer and ask them to switch it off. You may have to sign a declaration (for insurance purposes) and you will get a sticker to indicate that the airbag has been disabled. You will need to notify your insurance company as well I think.