TBH I don't think anyone has 'dropped' the headlining....
I've never heard it mentioned by anyone... even before we started
this website, so....dare I say, you could be THE FIRST !
There is no workshop manual for these cute little beauties, so my only
advice would be to take your time and be patient while doing it....
and take masses of pictures and notes every step of the way so that
eventually you can put build up a 'HowTo' to put in the Technical section of Interiors !
If that all seems a little daunting and you decide to give it to an
'indie' to fix, ask if you can be 'present' to take photos as they proceed.
(They may not like the idea of that, but say its for your own records,
then make up a HowTo later...tehehe)