Cannot enable menus in Appearance menu.

I’ve been passed a WordPress install to fix up and add pages to, using a custom theme built by someone else.

Under Appearance ‘Menus’ is not present. I tried a few different methods I read online to add the menu support to the theme but haven’t managed to get anywhere with it yet. I added “add_theme_support( ‘menus’ );” to the functions file and saw no change.

‘Menus’ is present when I enable the other themes. Is there anywhere else I should be looking other than functions.php or anywhere specific I should be placing the add_theme_support to the file?

Any help appreciated