Airbag Light on after new stereo install

Hi All
I recently installed a new head unit with 1 din fascia on my Megane RS 250 2010.
All works well but now the dreaded airbag light is on. Seems to be related to the passenger air bag.
I previously had an ebay purchased stereo which replaced the display unit in the centre of the upper dash. I pulled out all the cables associated with that so may have pulled one of the cables off the airbag. Just wondering if anyone has had this issue before and if anyone has an wiring diagrams available. I assume the airbag is just above the glove box so if I remove said glove box I may be able to check the connections ???
As usual this has happened just before its MOT is due. I guess I could try diagnostic software but not sure if you can get that for personal use??
Many Thanks for any advice.
Simon