Hello both of you,
I'd advise logging onto the Dukan official website and filling out their form to figure out your "true weight". One thing which is great with this calculating tool compared to pure BMI or our own favoured goal weight is that it takes into account so many other factors (age, diet history, etc) that, while it might well give you a higher "true weight" than your heart desires, it'll more likely be a "stabilisable weight" for you. You don't have to pay to join or anything, just give an email address to receive the results.
Meanwhile, Lulu, presuming you do need to lose 1.5 stones, 3 days' attack sounds about right.
Muller Lites are full of surprisingly sugar so, while they might be ok for some, others find they stall their loss so I'd advising sticking to Total 0% yoghurt at least at the outset (and certainly while on attack). Gamy, you'll probably be fine with one a day.
Why not open a diary in the diary section and post some menus and we'll see if we can help. Remember to have your oatbran each day (1.5 tablespoons while in attack, 2 tablespoons thereafter). There's a thread here with fabulous recipes. Don't just spoon it into a yoghurt as it's not very nice that way!!