As others have suggested, a DAFNE course might help, for several reasons:
1) it's a good way to tackle your GP/hospital. You can say to your GP, I would like to learn more about how to manage my diabetes, please refer me to a dafne course - and s/he may well not find that a challenge because it's not saying the GP is wrong, it's saying that you want to be proactive.
2) part of DAFNE is teaching you that you can eat what you want, when you want, as long as you cover it with the right amount of insulin. They also teach you what to do if you want to eat healthily. That might help the snack-craving thing. But you can eat 'healthy' food that is high in carbohydrates (eg lots of fruit) and be unhealthy if the insulin isn't right for it. So getting the carb/insulin balance right is the best first step.
3) I would bet that you will find others (with diabetes) on the DAFNE course really helpful in terms of hearing other stories, helping each other out, encouragement, and tips and hints from their own experience. It can be very lonely having type 1, and a huge relief to talk to others who have it too.
4) the DAFNE tutors can advise you on other insulins if you are having problems with Lantus as others have suggested. NOTE: you will have to go onto a regime of injecting more than 2x a day of novorapid though. If that is not acceptable to you then DAFNE isn't for you.
Here are some resources that might help.
First, this is a list of the areas that do DAFNE - you can get referred out of your own area to another course if you want to, I did that.
http://www.dafne.uk.com/downloads/DAFNE_centres_uk.pdf
(There's also a course called INSIGHT which I have no direct experience of, but apparently is very similar so if they offer that instead, try it)
Second, this website might help with assessing how many carbs etc are in your meals and snacks - they do a book which is useful.
http://www.carbsandcals.com/
hope that helps, good luck, let us know how you get on.