Also, just to add I average about 15k steps a day in working week, but I appreciate that I need to do proper strenuous exercise to actually burn the calories I need for weight loss.
You really don't. By all means, do cardio for heart health, for psychological health, just plain old because it feels good to do it. But don't rely on it to burn calories.
Calculate your TDEE, taking into account your PCOS. e.g. thepcosbible.com/pcos-macro-calculator/. Find 3such calculators online and take an average of all 3 answers (they may be slightly different).
Subtract 10-20% calories from them and then multiply by 7 to get a weekly target.
Realistically think about your week and how you want to distribute your calories to fit. e.g. if you are happy to eat lower on week days but want a bit more for weekends then allocate them like that. e.g. Mon-Thu = 1500 per day. Fri-Sun = 2000 per day, the average eaten per day is 1714kcal.
Each week day, keep 200 is calories aside for things you really like but that are not nutritionally dense. e.g. 3 hobnobs. Each weekend day think about reserving a higher number for these kinds of foods, e.g. 500 per day.
Use the rest of your cals to eat as nutriotinally dense food as you can, whilst still enjoying it. This will naturally tend to lead you to lower carb, or at least more complex carbs. For your exmaple diet above, that means replacing most of the choc, crisps, biscuits with something a bit better for you. e.g. you may find all that adds up to the same cals as a salad bowl or a small wholemeal sandwich that would go with your soup and help fuel you better for your day.
Eat like that for as long as it takes to get where you want to be. If that's going to be a long time then...
a) keep looking for foods you enjoy that are within the guidelines above.
b) give yourself permission to move to your total TDEE (maintenenace) calories anytime you are finding it really tough or you have special events, like Christmas. That still means counting and trying to eat right, but it gives you more calories to play with without reversing you into weight gain, plus provides a psychological break. You then cut cals down again when you're ready to keep going.