Humbugs are not always mint flavored. If they are they are usually colored with black and white stripes, if not they are golden. I used to buy these in tins for my grandmother at Christmas time. As Chris said they are hard but I'm sure that they had a more chewy centre.
Barley sugar is another hard candy. I don't think it has a flavour apart from the sugar it's made from. They do come as individual sweets but I remember them as twisted sticks that you could suck on for ages. I'm sure they are a good source of tooth decay.
Libby