The car used here is a 3 door GSI but the same methods can be used in any nova. Please take extreme care whem using any tools near the material as it can tear and rip VERY EASILY.
STEP 1
You will need to remove the rear side windows and windscreen, luckily here is a guide someone prepared earlier for this task
http://www.pngclub.com/forum/showthread.php?t=134531
STEP 2
Remove door rubber seals and tailgate seal.You can now see the edges are folded round the edge of the panels where the lining is hidden by the seals, carefully and with flat blunt tool ( i used a large head flat screwdriver with the sharp edges rounded with a file) begin to peel the edge of the material away from the metal edge, take your time here as the material is glued to the bodywork, go to fast and you run the risk of ripping the lining.
This is the slowest and most tedious task but the the most important.Once you have done this stage it should look like this
STEP 3
Grab handles now. IIRC Benn mentioned this method in another thread so i tried it and really liked it
Take a drill with a 2mm bit and drill a hole in the centre of the 4 small plugs but DO NOT drill completely through the other side, only about 10mm in like this
Then get a small self tapping screw and screw into the hole, using mole grips on the screw head pull the plugs out, try to pull out straight as to much movement can damage the handle as i found out ( more on that later )
repeat this process on all handles and the sun visor clips, you should have this
Also remove the rear view mirror, interior light and sun visors, i also had to remove the sunroof handle and rubber seal at this point, also the material is glued around the sunroof so this will have to be carefullly taken off
to remove the grab handles appply an upward pressure and if required lever very gently from the underside, as the next picture shows how the clips hold the handle in place, they are smooth on the bottom but had a lug on the top edge which can be easily broken.
once removed you can reuse these pegs to refit the handles (as vauxhall cant supply new pegs) by simply turning them round
STEP 4
Next is the support bars, there is only 2 with the tilt and slide sunroof but 4 iirc in a non sunroof car. on my car the first bar is held inplace by this plastic clip ( which i also broke ) simply unclip and allow the bar to turn and sag down, now with a little effort pull one side of the bar out of its plastic clip on the side of the roof
the last bar is held in place by 4 metal lugs, simply bend these out of the way and that should allow the headlining to be free.
on non sunroof models the 4 bars are held inplace by metal lugs, these just need bent out of the way to allow the bar to turn and sag down then relese one side from the plastic cllip at the side and the other side pops out too,
on mk1 models the headlining extends down the C post and is glued along both edges,
Remember kids, if its your first time then take it slowly, we dont want any accidents
cheers bazil
( i and png accept no responcibility if you get this so wrong LOL )