Congratulations Gemma, great results so far.
Dieting is largely about how you feel. Your body will give you warning signs if your plan is no good for you, but i suggest you get some decent high quality excersize in to minimize the lean muscle loss.
Remember when you come of ANY diet you will put back on some waterweight as your body rehydrates itself and reverses the diuretic effects of the diet.
Best of luck, and stick around here with us, keep us informed of your progress, good or bad.