vauxhall zafira roof lining?

my roof lining has separated from the hardboard,due to an over enthusiastic steaming of the carpet and seats, by mrs is ,there a 1) a glue that i can inject between the material and the board to get it stuck back together without it showing marks on the lining or 2) how do you change the roof lining ?? help my cars a 52 plate, old but i cant afford to get a newer car..thanks in anticipation of any help you may be able to give..cheers