Air bag light stays on
SEAT Mii (KF1_)

The airbag light has recently come on and wont go off.  I took it to the garage who said it was the airbag switch.  They reset the light but it very quickly came back on.  I don’t believe it is the switch but something else more basic.  I have checked the connections under the seat and they seem fine.  Has anyone experienced this and do you have any instructions on how to remove and check the passenger off air bag switch or any other checks I can make as the garage want £46 for a new switch plus a hours labour to fix, with no guarantees.  Thanks in advance