Help with losing a bit of weight

[namechange4this123]

So my weight seems to be creeping up and up at the moment, and today it finally hit 9st 2lb. This may not seem like a lot, at only 5 foot tall it almost puts me in the overweight category according to BMI of 24.8 (which I know is not all that accurate, but I see it as a general guide for trying to stay in a healthy weight range).

I think I eat medium healthy, but I could do a bit better:
Cereal for breakfast
Homemade packed lunch (usually sandwiches/salad) during the week, and similar at weekends, sometimes eggs or pasta
Dinner tends to be home cooked, usually meat or fish with potatoes/rice/ pasta and vegetables
I do snack on chocolate too much, and this is one of my targets to cut down on. Fortunately I've recently started a new job which has free fruit bowls lying around, so that should help.
I also am trying to cut out on fruit juice, which I drink a lot, and stick to water.

I am very unfit, and up until recently, I haven't been exercising much at all, but am now commuting to work by public transport and walking approx 45 mins per day, plus I am trying to go out at lunchtimes for a 15 minute walk, which brings it up to an hour a day. I can't afford a gym membership.

I'd like to lose approx 1lb a week, which sounds like a sensible amount, and ideally get down to about 8 stone in about 4 months, which to me seems a reasonable target.

However according to most calorie calculators I had looked at, I would only be able to consume about 1100 calories per day. This seems a difficult target, and most calorie counter apps e.g. myfitnesspal (which I have used before) will not let you eat under 1200 anyway. How can I lose weight healthily and at a reasonable rate, and how many calories should I be eating?

1100 seems low to me. I lost 5 stone doing a combination of 5:2 and mfp consuming 1200 cals a day on my non fasting days. I dont know if that's counted as a healthy way to lose, I just know that it worked well for me.

It is low. I suppose I could eat 1200 a day, and just accept it will take a bit longer to shift the weight (maybe 5 months instead of 4). Ideally I wanted to lose it in 3 months, but the calorie allowance was so low (about 1000 calories) it just doesn't seem possible.

Maybe I am setting the bar too high. In trying to ultimately get down to 8 stone (a loss of 16 lb), when I currently weigh 9 stone 2lb (128lb), is actually attempting to lose 12.5% of my body weight, and maybe this is too much to lose in 4 months.

I'm not a big fan of the 5:2 and other fasting diets. I'm not saying it wouldn't work, I've never tried it, but I just don't feel I could go a whole day with so little food and be able to function normally.

I think if you stuck to about 1200 a day even without any fasting you will lose the weight easily in that time frame. I lost the 5 stone in about 6 months (which I know is faster than would be recomended)