heinz don't do WW with a protein thursday, wouldn't work, would be fine for maintenance but I don't think it would get you over a plateau.
However no need to follow dukan strictly either, its about totally cutting out:
a) the refined carbs - sugar (including honey etc), white flour, pasta, fruit juice, white rice, and all processed foods
That might be enough to get you over the plateau - but if it isn't then try cutting:
b) anything else that will spike your insulin levels - fruit, wholegrains, starchy veggies (carrots, parnsip, peas, corn), pulses, even dairy
Clearly you wouldn't want to cut out b) type foods for that long, and they'd be the first to reintroduce when you reached your target.
re: costs I don't think its that expensive, I eat a lot of:
- tesco's own brand cottage cheese
- tesco's own brand fat free yoghurt & fromage frais
- tesco value eggs
- tesco frozen white fish (coley, haddock)
- chicken and turkey breasts
- tins of tuna - buy on offer
- tins of sardines, mackeral etc
I don't eat much meat - probably only a couple of times a week max. And even then usually mince.
I don't do low carb pasta or anything similar. I prefer to avoid processed foods, I think eating "clean" is the best way to loose and maintain weight loss and most low carb foods come up this category.