This is what I'm planning on having to eat to try and reach my ideal weight.
-Cereal like fruit and fibre or special k for breakfast
-Brown rice and skinless fish for lunch
-Small portion of pasta with chicken/quorn for dinner
-Possibly fruit as an occasional snack

I will be attending the gym 3 times a week and doing some walking.Do you think this is acheivable?

That does sound like loads to lose in short space of time! Also no veggies and fruit in the diet does not sound too good to me.
Also Special K does have a lot of sugar in it too, not a diet cereal at all.Porridge is really good but beware of microwavable sachets that contain loads of sugar too. Lunch should be your bigest meal with lots of veggies.

I lost 4 stone last year within a few months but because I was following such a strict diet I have now put all the weight back on and a little more, my doctor said that doing it more gradually would help the weight stay off

I have tried loads of diets in the past, with success, only to put weight back on immediatly after.

I have been trying hard for the last ten weeks, including giving up alcohol, counting calories and eating fruit till it comes out of my ears and have only lost around half a stone. I have sticked to around 1,000 to 1,400 calories a day, so am feeling pretty disheartened!I will stick to it , as I am feeling a bit healthier. I have around two - three stone to lose

Count me in as well to lose weight before July!