No one likes saggy things especially headliners.
Mine has just started heading south. Any tips for making it perfect again?
I’ve not seem that before, how easy, or hard, is it to peel the lining back and re-glue?
It feel very well stuck around the edges TBH. I did consider peeling it from the sides and re gluing but it was stuck , solid!
Id suggest then, removing it and cleaning. Its brushed nylon material, so recover it yourself using some trim adhesive. Spray glue would soak into the trim and mark it.
Thanks for the pointers. Ill watch some youtubes with your advice and get on it!
Had to replace mine for the same reason. In the end bought new fabric from eBay with spray glue as it wasn’t possible to salvage the original.
first attempt I sprayed the whole roof before laying the fabric. Wouldn’t do that again, suggest doing it in sections so the glue doesn’t go off before you are happy with the finish
Hi All,
I’ve just replaced mine as it was saggy pretty much all over 
Bought 2m of foam backed headlining from Martrim:
https://www.martrim.co.uk/car-trimming-supplies/headlining.php
who also supply the spray glue.
I peeled all the old stuff away first. All the foam backing had disintegrated so it wasn’t reusable but kept it as a template so I could pin it to the new material and cut round it. If you’re attempting it just take your time. Allow the glue plenty of time to cure (about a minute) before putting the headlining in place.
I found the hardest part was the screw holes on the separate panel. I might have to do that bit again as still not completely satisfied. 
Thank you , I will investigate
Just noticed I have the beginnings of the same issue on the side of the roof panel and splitting of the material around the 3 fixing points on the front retaining pad.
The current material is a “Hole of Calcutta” black type of thin felt with what feels like a foam backing.
I am considering recovering the roof with a mid grey alcantara and the four fixing pads with grey carbon pattern leather to match the doors, hopefully it will also brighten up the interior, a little less gloomy.
That should look good.
Take photos and keep us updated 
I replaced mine few years ago as it was saggy got some foam backed headliners, then did dimaond stitching over it and then glue it after good cleaning.
And did I the doors to match it.
That looks brilliant
Like that a lot.
My headlining started to delaminate. Allon White’s did a terrific job in black alcantara, and I seem to recall the price was very fair, considering the work involved in removing the foam backing.
Happy customer.