The roof lining is coming away

The fabric roof lining on the inside of my Disco is coming away where it meets the top of the front windscreen. Over the last few months as water has been leaking in (despite lots of sealant being used) the fabric has been coming coming away and the section that joins onto the top of the windscreen on the drivers side only is currently hanging loose over my head.
How can I fix this (easily as poss!) or will it have to be a trip to local Landy garage?

get another roof lining ! if your has been wet they usually never fit right as the stuff there made of goes all floppy. if ya wanna remove it ive got one you can have for free !