When trying to lose weight as a diabetic, there are generally two schools of thought. Some go for low-carb and others simply go for less food overall. The problem with low-carbing is that some don't realise the calories in the low-carb foods, so still eat fatty foods.
I have been losing weight steadily over the past 8 months or so, since I had a leg amputated, simply by eating a little less than before. After a while it becomes the norm and the weight does slowly drop away. I agree with "mo1905" that half a stone in 5 months is a good loss for you.
Personally, I found that in the past I was eating to my insulin intake. After taking a carb-counting course I have managed to eat less and adjust my insulin to the carb intake. Having fruit for breakfast usually means that I don't need any fast acting insulin at all in the morning and having a salad with something like smoked mackerel also means minimal insulin at lunchtime too. I'll still have sausage and mash followed by ice-cream in the evening.
So, although I don't deliberately follow a low-carb diet, my calorie intake has dropped by quite a lot over the day. And when all's said and done the simple fact is that eating less calories than you burn will create a loss of weight