You have to take the Sunroof out to get to the brackets. Here is the procedure for my w126, hopefully it will work for your car.
First of all the headliner has to come out, There are 4 snapon plastic clips at the front of sunroof. Here is the pic, I copied it from Thoms's website which is a great tech. resource.
Once you take those clips off, pull down and then slide the headliner from the front. You have to have your sunroof half open so you can pull the headliner out. Once it is out, now you can see on both sides of the sun roof pannel 2 screws attaching the pannal to the angle brackets or lifters. Unscrew these screws on both sides and then slide the sunroof out from the front. Now you can reach to these angle L shape brackets, they are attached to a central piece which is attached to the motor cable.
These are fairly expensive parts, about $140 US dollars a piece, hopefully they are cheap in Australia. I end up buying the whole sunroof from a junkyard for $100.00 and replace the machnism.
I hope it help to solve your problem, feel free to ask any questions you have.
Keep us posted.