Firstly, thanks for sharing and hopefully you've found some of the previous comments useful.
I would suggest you:
- Avoid Slimming World/Weight Watchers, and any thing that requires you to pay for help that is ultimately not sustainable
- Try not to listen to the views and opinions of people who clearly have no idea what they are talking about or have even tried what they are suggesting
Portion control is difficult (trust me, I know first hand), and the way to approach this is to slowly reduce the size of your meals without stepping out of your current comfort zone. It's like anything, time; effort, patience and persistence will ensure you're able to sustain any weight-loss you achieve (which you definitely will!).
That said, I would recommend the app MyFitnessPal and set up your goals, target weight etc (SET REALISTIC GOALS PLEASE!) and start there.
Google 'macronutrients' this is something MyFitnessPal will help you focus on and avoid watching the calories you eat and pay more attention to the amount of grams of protein/fat/carbs you consume.
Your back problem may be closely related to your weight and once you get a handle on that you'll be able to tackle the back problem a lot better... Additionally, keeping up a consistent stretch regime (no more than 10-15mins) per day will help. Eventually you'll increase the time without even realising.
Approach a specialist regarding your back and stay away from silly diets that will not work because, attacking this and conquering it yourself will be so much more rewarding.
Also if anyone has mentioned 'Herbalife' steer insanely clear of that crappy advice, it's not the 'shakes' or 'shake formula' that will make you loose weight, it's the fact that the fad asks you to limit you food considerably that will promote weight-loss (basically they'll want to starve you a bit to sell their product and hopefully make you a distributor in their ridiculously flawed business model).
So in summary:
- Install MyFitnessPal on your phone
- Avoid any and all diets/schemes etc...
- Gradually reduce your portions
- Watch your macros like a hawk
- See a specialist re your back
- Don't watch anymore fitness dickheads that will make you feel inadequate
- Be frikkin' awesome and deal with the problem yourself so you're the one patting your own back when you're several sizes smaller