Hi Eliot,
Well I can't advise you as you ultimately you have to make your own choice and choose a regime which suits you best. Having said that I can recommend Cambridge Diet. I have been doing it since Feb and have lost 5 stone. It has completely changed my life and I am so grateful. I think it is the best thing in the world but then again I am very biased. It's not all plain sailing, the first few days can be awful but I have to say I didn't find them that bad personally. And you get used to it very quickly.
I can tell you a little bit about it. Firstly you visit a counsellor and they will tell you all about it and what to expect, weigh you, measure you and take "before" pictures. If your BMI is over 40 you may have to have medical approval from GP. The diet consists of tetra pack of protein drink, shakes, soups and bars. Weigh in each week and there is plenty of support on here.
I know that when I finish CD I will have to maintain and change my eating (and drinking!) habits from what I was doing previously otherwise it will pile back on again.
The most important thing for you to do is to research a number of diets and decide from there which one suits you. Once that decision is made then you need to be in the right frame of mind and when you feel you are ready then start. Drinking water is key so in the meantime you could increase your water intake and that alone may kick start losses.
Anyway whatever you chose, good luck and keep the faith.