Just an update for you all;
After re-soldering all of the wiring looms across all 6 airbags, the airbag light had still not disappeared.
However, the garage now suspects a faulty/ used passenger/ drivers side pretensioner, due to a shorter length pretensioner on the passenger side, indicating that the airbag has been activated at some point and thus the pretensioner tightening in the event of a bump.
What has made this so hard to eventually identify is the fact that firstly; the car is not registered as having been involved in an accident; Secondly; the body work is in fantastic condition, with no sign whatsoever of a bump with all paintwork fantastic and no cracks, marks etc; thirdly; upon inspection by the garage, there is no damage to the chassis, so it may have only been through a non damaging incident, that the airbag has been activated and pretensioner expiring; and so it has only been through process of elimination and sitting in the car for a good old head scratching moment, that the garage has found what seems to have been the problem all along!
I have also done a bit of research of my own and found a similar encounter by a Renault Megane owner, documented on the Renault forum.
Hopefully after 2 painstaking weeks without a car the problem will finally be fixed.
Furthermore, I hope this comes as a helpful suggestion and remedy to anyone else who is having the same issue.
Many thanks for your input and suggestions, as always it is very much appreciated and I'm sure it will come of great use to me and others in the future.