I removed the entire sunroof tray to work on it, but it retrospect I can see that it probably wasn't necessary. That said it got me better access to the drain pipes which got compressed air blown down them.
The actual sunroof repair didn't go as well as hoped.
The two front screws had to be drilled out, and that damaged the rack piece that they screw into it.
As someone said the replacement once aren't that good and don't slide freely.
Also there is an arm on each side that connects the telescoping double rack thing to the frame with a eyelet clip.
On one side the end seems to have rusted away so that bit isn't possible to fix properly.
I am deeply unimpressed with the mechanism. It is over complex and full of cheap, underdimensioned plastic parts. One bit of dirt anywhere in this thing and iw will be game over.
Anyway the near glass is in and I think it won't leak anymore, so that's a result.
The headlining isn't great though.