Flossie, the book is called Deceptively Delicious.

Swapping dinner and lunch can work - I did that for a while with DS1 when he was about 15months. It did make a difference for a while. It's certainly worth a try. As for whether to remove the meal after one piece goes on the floor - I don't think it matters too much. You sent the right message - you throw food on the floor and I'm not going to get upset and you're going to go to bed.

The other thing you could try is to not give afternoon tea, and not too much to drink in the afternoon. It might be that she's just not hungry by dinner time. And if she is tired, this is even more likely - they don't tend to eat well when tired. TBH my 3 1/2 yo still is often not very hungry in the evening. I just make sure he gets vegies, fruit and some meat during the day at least a couple of times during the week, to make up for the nights he might not eat much dinner. It often doesn't seem like a lot they are eating, but it can be for them, and they really don't need a big meal before bed.

GL, it sounds like you are definitely making progress. Well done.