I think a wieght loss of 2.5 stone is great, I was just banded last week by Dr Patel from Kings and I hope in four months I will be able to report such wieght loss.
although I've only had my band for six days, I know what it feels like to be seemingly eat less but to not see the wieght loss u would expect. I would advice you assess what and when you eat. At 240lbs I have friends who at skinny minnies who eat more then me yet I cant shift the wieght.
What I have noticed from the way they eat is
1- they all have breakfast, I used to think not having breakfast was a good wieght loss tool but now I throughly advise everyone to have breakfast.
2- they drink a lot of water, my go to drink is either a latte or a can of coke, apart from the calories they also dehydrate the body and deplete nutrients. So I would say get lots of clean fluids throughout the day in the form of water, green tea and herbal teas etc....
3 - Protein before carbs - firstly up your protein intake is a must, but also eat your protein in meals first before your carbs. In regards to carbs keep them as close to the way nature made them as possible.
4- Avoid processed at all costs - aside from taking up valuable calorie intake, modern day processed food is mentally addictive and chemically destructive especially to the overweight. If you consider all the hormonal and metabolic hurdles wieght loss involves, processed food essentially makes those hurdles impossible to get over.
4- Fillers vs treats - because of my job I would often grab a chocolate or biscuits to fill hunger throughout the day. Try to see these as treats and not fillers. Look for more health nibble food like nuts, seeds, cheese squares, raw veg
5 - Discipline and willpower - the magic ingredient
Also you may try changing your exercise regime add some weights and HIIT, as I find your body gets used to the level of exercise quite quickly.