Hi Ladycook61,
It sounds to me as though you have cooked the mix for too long. I`ve checked my recipe and it should be boiled to a temperature of 118C/245F. Once the mixture has reached this temperature it should be removed from the heat. allow the bubbles to subside and then pour into a greased tin. You should mark the mixture into squares, using a buttered knife when the mix is half set. Finally, as I`m sure you know, after you`ve poured the mixture into the tin, soak the pan in cold water.
A fantastic range of sweets can be cooked at home or in a commercial kitchen to serve with coffee. However, they are all temperature sensitivie and it is worth investing in a sugar thermometer or perhaps using a digital probe. For example, soft vanilla caramels should be cooked to 121C/250F, honey caramels to 130C/265F and walnut caramels to 124C/255F. The reason for the different temperature is the need to remove water, by boiling to achieve the right degree of sugar saturation in the finished product.
Hope this helps,
Archiduc