Do you have a menu selected in Appearance > Menus? I’ve seen some themes where the menu doesn’t render correctly if you don’t have a menu assigned to the location in Appearance > Menus (which would mean it’s using the “fallback” function to create one automatically).
Yes, I’ve been using this theme for a while with complete menus and drop downs and it was fine, then I was trying to change the padding and line spacing CSS on my style sheet and think I changed something which messed it up as I’ve been using the Pure & Simple theme for ages with no problems but was tweeting bits as doing a bit of a rebranding
I managed to sort it. I just restored all the original database settings. Started from scratch again from back ups, used the WordPress Database Reset plugin. Not sure what happened to make it go wrong but I’ll be more careful in future!