Im posting this to help others who have just found this/will need it.
Today I fixed my airbag problem with this software and cables

. Total cost under €50. I had briefly used Rosstech stuff before, but if you havent used any code reader its easy and makes life way easier when dealing with problems.
If someone is browsing this in the future - to save you some time, I wish I could of - this is what you do to find your problem....and fix it. Luckily I had a easy fix.
1- Buy these cables.
from here
http://www.idiagnostics.co.uk/ ....You can browse ebay for cheaper ones but you have to modify them as different parts of the ECU works on different pins. e.g. Airbag is separate to engine fault codes, some are chinese crap. Its just easier and you can access everything.
2- Download the free trial (you should definitely buy later anyway) and READ the first few pages of instructions. The 'latency' settings stuff is important. It will make sense later. Just follow it. If you can read you can do it.
3- Connect the blue (KKL VAG com) & Red (Airbag) leads together...plug in...select vehicle....select airbags...select scan....-it tells you what airbag system you have. my stilo 1.6 active was SIEMENS MY99 Airbag (2F-2P-2L-2T-I-S-C)...click that option and connect...check 'errors'.....I had 6 or more stored in memory. Copy these somewhere, take a screen shot or something. Its just as a reference.....then clear faults and see what remains..THIS is your problem you need to fix.
4- Everybody's codes/problems will be different from here.
Mine was code '21-Curtain airbag squib'....Through this post
https://www.fiatforum.com/tech-talk/268442-stilo-airbag-problems.html found out it was the airbag connection in the rear pillar drivers side. As done by many people on here, I disconnected the battery, waited 15 mins, disconnected orange plugs and sprayed contact cleaner (€6 euro from halfords), let it dry and reconnected.
5-Whatever your fix was, when your done then get the software back out, go to the airbags again, clear faults and if the airbag red light stays off your done!!
The light may come back in the future but for now its perfect. Can get through the NCT/MOT anyway. I need the full version to do some more stuff so Im gonna buy it...then a few mods at last.