You can do it
There are a lot of people here that have lost huge amounts of weight, and if they can do it, then you can too! It's important to follow a healthy, balanced diet that includes portion control or calorie control.
I've read some of your posts describing what you eat, and you admit that you don't choose healthy foods. It's not just about the number of calories you consume, but also about the types of foods you eat. I fully understand when you said you want to enjoy your food and eat foods that taste good. There are a lot of healthy foods that are good. I spent a whole year in England a few years ago, and became familiar with some of your options, and I'm sure you have even more choices now. I particularly loved the Count on Us ready meals at Marks and Spencer. I still talk about them, lol, because they were so delicious. Have you considered taking the ready meal approach, so you don't have to put as much thought into your meals? Maybe you could do something like have fruit and either yogurt, cereal, or oatmeal for breakfast. Have a good sandwich and/or salad for lunch, with fruit for dessert. Have a healthy ready meal and extra veggies for dinner. Then have one or two snacks to round it all out.
It sounds like you are having problems breaking the crisps and chocolate habit. With careful planning, you can still enjoy them, within reason. If you do well for all 3 meals, for example, maybe one of your snacks could be one (single serving size) bag of reduced fat crisps and a light chocolate treat. Perhaps knowing that you don't have to completely give up your favorite snacks will help you to introduce other healthy foods into your diet.
Maybe you could try something like that for just one week, and see how it goes. Don't weigh your self or focus on pounds lost. Just focus on making healthy changes to your diet, since that seems to be the most important problem you are facing right now. Also keep exercising. I noticed you said you do cardio DVDs and use the treadmill and trampoline. How often do you do this?
Small changes can add up to big results. There is a diet program called Change One that teaches you how to make small changes instead of jumping head first into a diet. For example, your first goal is to eat a healthy breakfast. The rest of the day doesn't really matter, you can diet or not diet. But that one meal MUST be a good, balanced choice. You do that every day for a week. Then the next week, you not only continue with your healthy breakfast, but you also tackle lunch. Other weekly tasks include healthy dinners, snacks, exercise, stress reduction, and more. This is great for someone that feels overwhelmed by their diets and want to ease into it.
There are a lot of options you can choose, these are just a few that might work for you. Whatever you do, keep in mind that you are making changes that will last a life time. The diet never really ends. Once you do reach goal, you still have to make wise choices to keep it off. So, it's important to be careful how you lose it, and get used to healthy meals now.
Please keep us updated! When you try new things, let us know how it goes