How are you getting on @Cornflakes44 ?
It's really common to plateau after a while at Slimming World. There are lots of reasons, varying from letting your syns creep up without noticing, same with portion size of healthy extras, eating more of the denser free foods and less of the speed foods and so on.
The first thing I'd urge you to do is to have a trip to the doctors to rule out thyroid, women's hormonal or pre-diabetes causes, especially if you are 40+ (but also even if you aren't). I'm not knowledgeable enough about what hormones do after stopping breastfeeding, but it wouldn't surprise me if they may still be a bit out of sorts and be taking a bit of time to return to normal, and that might be having an impact too. Breastfeeding obviously burns absolutely loads of calories so you are burning less calories from not doing that any more - I wonder if you might need to adjust your caloric intake down, now?
Other things to try:
It's easy to get into a rut eating the same old things, and changing it up can kick start weight loss again - try increasing your speed foods, try eating different free and speed foods and so on.
Do you normally eat a fair bit of potatoes/pasta and rice? Slimming world doesn't really differentiate between carbs and lean meats any more, yet there's good evidence that supports eating less carbs for weight loss, so try a couple of weeks doing the old style red days (if you remember them, or if not just focussing on speed and protein foods).
The other thing I'd do is to log your food in something like my fitness pal as well as whatever you do for slimming world, to see if you're eating significantly more calories than you should be, even if it's on free foods.
And moving more - whilst normal levels of exercise won't burn enough calories to make you lose weight in and of itself, even just things like going for a walk at lunch time or in the evening can help boost your metabolism and that can help you to burn more calories.
Best of luck!