Ooh, we get to advise a GP! (Sorry, that is making me gleeful).
You have an impaired metabolism, and carbs will
always be a problem. You can still have carbs and reduce portion size, but in all likelyhood that will mean you will progress to full fledged T2. While going hungry in the meantime. You already were borderline diabetic with the HbA1c of 6.8. Just barely still in the prediabetic stage. You missed a T2 diagnosis by a hair. Remember, the weight came on because of your impaired ability to process carbs: When you're insensitive to your own insulin, rather than help you burn off the blood sugars, it just stores the glucose in available fat cells instead. You don't get diabetes because you're obese (or TOFI: Thin Outside, Fat Inside), you get bigger
because you are becoming a diabetic. It's when the cells can no longer cater to the storage demand, that the glucose spills out into the rest of your body, because it's got nowhere else to go. Blood, organs, saliva, tears. Voila, T2.
Jo