This is a great recipe, I hadn't made them for awhile so I made some yesterday for a bbq we had today with my sister and her family who are visiting from Canberra.
I used a Crunchie chocolate bar. It's a very forgiving recipe as well, as I got to the end of making them and realised I hadn't added the sugar. Oops, I adding it and whizzed it up a bit and they still turned out fine.
I gave this recipe to my SIL a couple of years ago and she makes them all the time (she doesn't have a TMX, so she just makes them using a hand mixer). It really is an lovely and easy recipe.