Many thanks for the instructions.
Will disconnecting the airbag trigger any error codes?
Found this service manual online and it talks about disconnecting the yellow and orange SRS connectors next to the centre console before removing the steering wheel airbag. So I don't really need to do this?
http://www.volvotips.com/service-manual/volvo-960/Volvo-960-S90-V90-steering-column-service-repair-manual.html.