You could try hiding veggies in other things - I think there is a cookbook (deceptively delicious, I think it is called) which has hidden veg. I also make cheese scones with loads of veggies puréed up in them which are a real favourite here and they make me feel better on the days when not much is going in! You can make them with goats or sheeps cheese (manchego works really well) - I have an mpi boy as well!
Another thing that we did when we were having major issues with m eating was to give her the Ella's kitchen veg pouches as snacks - not a cheap option, but she absolutely loved them and they were a real treat. Again, saved my sanity when she was living off sausage mash and beans or biscuits raisins and cheese!
One other thing - as the girls have got older, we have related the "reward" food to hunger. So if they are "not hungry enough" to eat the thing that they don't like then they are not hungry enough for yoghurt either. I quite often find myself saying that they have to eat a certain amount of a food to get their yoghurt, and then if they say they are hungry after then they have to go back to the main course.