I get PM's about issues and sometimes the discussion should be made public.
Here a preFL wagon owner's SR (sunroof) mechanism (mech) is working the rear section but not the front.
Its possible to fix various bits on the mech, there is a thread here where the issue was a broken roller on one side.
If you get stumped I would source a second hand sunroof locally.
They're common afaik between pre and post.
The last thing I'd do would be to get a professional on the job due to it being a very time consuming procedure, UNLESS of course you can get a really good quote from a trusted pro with experience, one that beats your own downtime/price per hour w/ parts.
The removal process is to read the fsm on the roof trim uninstall, some of the handles unscrew then must be pulled laterally to release them (slot lock, longitudinal) you'll need time patience and a covered workspace.
Then remove the sunroof glass, marking and separately bagging the shims that set the glass height so you can reinstall in order.
The mech is much lighter w/o glass of course!
Take lots of photos and stay organized to ease reinstall.
If swapping a new mech as I mentioned don't play with it as the sides could become unsynchronized.
IIRC there is a sunroof reset procedure in the FSM.
Coincidentally I'm doing maintenance on my sunroof atm as the motor is crapping out.
I'm going to carefully clean and dry-lube as much of the rails as possible and swap in my spare motor.
Then I'll service the old motor, I think I used too much lube last lime or too much graphite powder or not enough of either, or the brushes are worn out or sticky.
When I redo my headliner in charcoal macrosuede, I may delete the blind for less drag on the system.
The Rob Tait Tinter sunroof tint is that good!