Goof off, oops, or laquer thinner will remove the adhesive.
If you have not removed the sunroof frame do so as it is best to wrap it around the edge just the same way the window glass area is fitted.

Here's a few photos of the work in progress. Not a lot accomplished yet, but I learned that removing the rear interior trim section requires removing the sunroof, something I was hoping to avoid. Now that its out I've found a few failed rivets in the frame and the sunroof section of the headliner is due for repair/replacement as well. Lotsa time spent cleaning things up. Just finding something that would remove the weatherstriping adhesive. WD40 has worked as well as anything I've tried so far.

If you want to go black with the headliner i have used headliner or vinyl dye. My local automotive paint store sells it and it lays out beautiful, i also did sun visors with it.
Don't cut the sunroof area out until the headliner is completely fitted. As you are pulling and stretching moving it around to get rid of the wrinkles you need that area to resist the stretching somewhat, the last thing you want is for it to be too short due to having moved the headliner around to fit correctly.

Thanks, I appreciate all the feedback. Have some photos but forgotten how to use the big green button with an iPad, as I recall it’s more PC friendly.

Broke out the headliner I purchased a few years back, it’s grey not black like the rest of the interior trim. Not sure what I was thinking there. Car is black on red. Hmmmmm Gonna be interesting. 

Using the standard saloon headliner, the only option of which I’m aware as Masal suggests. Will make the cutout for the sunroof at some point during the install. How that takes place and what gets secured first is the question.

Gonna be raining here forever so I've got lotsa time, hoping for the patience required.

 

Thanks all, hope to make some progress this weekend!!

No more glue stains for you

The tape i used : Double Sided DUCK TAPE

Amazon = 7.35$

 thin= has a blue backing to pull away= strong
 is 1.4 wide I know i cut it into half strips for the application.

https://www.amazon.com/Duck-240200-Double-Sided-1-4-Inch-12-Yards/dp/B002O16SHW/ref=sr_1_3?ie=UTF8&qid=1516993411&sr=8-3&keywords=Duct+tape+2+sided

Who,s two sided tape was it? Thanks

Binder Clips are great
Patience
Warm or HOT day
 Let it strech = go do something else let it rest + Strech some more.

 Last headliner I did = I used a Great Very thin Two Sided Tape for all edges. instead of glue.
   No spraying mis sprays anywhere and so far 3 years later its just as good as day 1...
   The tape let re postionging go well too =

a helper on both sides is also good for pulling in multiple directions

go ahead and get NEW crossrods.. as old plastic tips like to break under new stress.



Take your time.. Don't trim anything until you're nearly Done.

The corners are the Worst part to tuck = strech= stick etc. along with C pillar covers ( just finkey to fit in all the edges)

Binder clips work great! The stronger they are, the better. Clip it at every opening then pull tight at the front and adjust the clips. Keep doing this at every opening until you have all the wrinkles out. Let it sit for several days and periodically check and see if it needs tightening. Adjust as needed. When you goto glue it I'd suggest one person in the car and one outside. Unclip and spray, stretch and reclip it. Don't trim anything until it's done and dry. Also, get the best 3M spray glue for headliners available. Good luck!

The majority of Mini's that have sunroofs were fitted after the sale and came in many different styles and configurations so i doubt anyone is making a specific headliner to fit any sunroof models. As the sunroof will need to be removed to fit the headliner purchase a stock one and cut out the necessary section which is the way every aftermarket headliner is done. I would glue the edges first and do the cutting later when the glue is dry.
The one thing you need plenty of (apart from patience) when gluing a headliner around the edges is plenty of clips to hold it in place while you adjust to get the wrinkles out and while it sets up. The best ones i have found are the binder clips which any office supply place sells.
Do not apply too much heat when fitting the corners as the material melts very easily.

Pictures please, i have a sunroof also, cant find a headliner anywhere

Removed headliner when I replaced wiring harness several years ago. Thought it time to replace it.
Sizing it up as a DIY project l’ve viewed what I found online and decided to give it a shot.  Windows are out and making a list of whats needed. Mine has a sunroof which will add a few challenges. First of which is trying to remove the rear interior sunroof trim piece. After removing the 4 screws it remains solidly in place. Welcome any tips and suggestions towards a successful result. 
Thanks