I've got about the same as you - I've lost just over 2 stone since February.
I'll be honest and say that I had loss of appetite/nausea for the first few weeks after starting a new medication but I used this to my advantage as it was easier to break binging habits when I didn't have my usual appetite.
I've continued with what I feel are sustainable, enjoyable and healthy changes though, and it's working without the usual mental battle to avoid food. It sounds like maybe Slim Fast might give you the same head start?
I walk between 1 to 3 miles a day (not always in one go) and if I don't manage it, I don't beat myself up. I have nothing to eat until around 10.30am when I'll have a piece of fruit l, a handful if nuts and coffee with almond or oat milk. Lunch is salad with loads of veg and usually cheese/avocado/coleslaw/egg or a wholemeal bagel with goats cheese/low fat philli.
Dinner is whatever I fancy within reason (I'm not eating takeaways or big portions) - I tend to keep my calories low during the day and then I can stress less about what I eat at night time and I can generally have what everyone else is having with some minor adjustments.
I have changed cow's milk for oat milk then switched again to sugar free almond milk which is very low calories and seems to work fine in cooking as well.
If I fancy chocolate I've been buying dark as I find a couple of squares of that is plenty and I don't crave more.
The biggest change for me is that I've stopped eating meat. I find I don't tend to overeat the same way I did if I was piling big portions of bolognese or chicken curry on to my plate.
I've avoided processed food as much as possible, with the exception of the odd plant kitchen sausage when hot dogs are on the menu. They're actually nicer than the meat ones.
I've finally accepted that this weight wont come off quickly and I feel different this time. If you want a buddy, it would be nice to have someone going through the same to share tips with!