Hi Sim, welcome to the forums!
I have hypothyroidism and could not lose weight no matter how hard I tried. If you look at my profile you will see I hoped to lose 2 stones on this diet. I didn’t believe it was possible. Some time ago I had lost 2 stones, 13 lbs and I am staying stable while I have increased my calories.
I’m sure this will work for you too as it is very hard to lose weight when you have hypothyroidism.
Good luck π