I'm 10 stone - and lost most of my preg weight within 4 weeks. However pre preg was 9st 7lbs and even slimmer for many years. I've been told I will lose the 7lbs when I stop BF. I'm exercising but having quite a lot of sugary snacks I never normally would crave. My face looks better for the weight though! And I'm 43 with 2DDs now. Only thing is my size 10s are tight but am too small to go up to a 12?!
I found with both babies I couldn't lose that last bit until I stopped breastfeeding. i was similar pre preg weight, and the last half stone just seemed to stay on until I weaned them, then fell off fairly effortlessly. I think its something to do with your body retaining fat stores to make milk or something..... Its annoying though, as you spend so long changing shape.