Op, I'm sorry you're getting a rough time but you know your problems, you know what is wrong but you're not doing anything to help yourself.
You listed a normal diet day. It's terrible if I'm honest.
Toast x 2 if I'm at home. A peanut butter sandwich if I'm out
Something like porridge would be more filling. I know you don't like eggs, fruit, yoghurt etc. but more protein would help you feel fuller for longer. Get out of the mindset of 'breakfast food' you could have lean chicken and avacado/tomato or something?
Lunch I eat things like a supermarket meal deal (sandwich crisps and drink) or a salad from subway or a salad from home.
More bread and crisps. Even the low fat ones are shite. Salad fine, but are you putting dressing on? It all adds up. Stop grabbing things from the shop, be prepared. It means putting the effort in and planning but its worth it. Get a flask / thermos and take in soup? Lean meat and veggies, brown rice and veggies?
Dinner I make pasta, shepherds pie, lasagne, sausage casserole, curry etc. I have a large portion of that. Maybe bread too, either before that or with dinner.
Do you really need bread with a large portion? Ditch it, you don't need it! It's habit! If all made from scratch then fine, look at your portion sizes. You admit they are large, start scaling them down. Only plate up 3/4 of what you usually would and replace with extra veg or salad. Do that for a while and drop down another quarter. If you're not making from scratch there are lots of hidden sugar / calories.
Snacks in the eve a bowl of cereal or biscuits or whatever other snacks are in the house
Why are you snacking? Boredom? You say you don't have time to do any other exercise but you have time for snacks.. take yourself out for a walk. Run up and down the stairs, do something to occupy yourself.Go out, see friends, play a video game, play an instrument, learn a language.. there are loads of things you can do to occupy your time that doesn't involve food.
Feeling sad - do something that makes you happy that isn't food! Get out of the mindset that food is a treat and food makes you happy because it doesn't. It's making you fat and miserable! Get your nails done, get your hair done, buy a new top etc. Food isn't a treat, you're not a dog!
Can't run, walk more. Can't walk, dance, skip, roll around, just move! There will be something you can do! Do exercise from your seat with your upper body! There are loads of exercises that you could do while your diet lets you drop a few stone to make it more comfortable to do more intense exercise.
It really is your mindset stopping you.
I say this as I totally understand. I'm 17 stone at 5foot I'm morbidly obese, and I know all of these things. I know what I need to do. I know when I need to do it. But I don't.
Exercise, meh cba. I tell myself oh I've got a headache, my ankle hurts, I don't have time, but I know they are excuses. That's all. As much as you're being defensive and say you're trying, you're not creating these barriers you are, and you know you are. YOU are the only person that can change YOU!