After 18 months of no sliding back of the sunroof I managed to get it to open with brut force and ignorance. The problem seemed to be the old 'sticky draw' problem. One side was moving but the other wasn't so I levered the side that wasn't moving and it popped open. After lubricating all the bits and aligning the two sliders I put it back the handle expecting it to work properly. But it doesn't.
Does anyone have any idea why on side doesn't seem to move as well as the other as it was nice having a proper sunroof for 2 minutes and I would like longer.
It may not help and isn't the same as fixing it yourself but the factory roof on my Astra GTE '89 jammed shut ( only the tilt would work). It looked as if it was jamming on one side only. After fiddling with it for a couple of days and getting nowhere I asked the local dealers how much to sort it expecting a "hundreds of pounds" quote and they said max 1hr labour (£35) and they do quite a few as they are prone to jamming
So took it in and they fixed it - £35 exactly and works perfectly now - have been enjoying the sun all week.
Sorry if this doesn't help,