OK, thanks Kevin
As you can tell from my other post, I am trying to find ways to (lawfully) increase my training data. The idea of using all of the data was recommended by @jeremy but I still have not found a way to work out how to do that!
Another thing that puzzles me (if I understand it correctly) is that our augmented data is only used in testing via the .TTA method. I thought that we should have the augmented data available to increase the size of our training set!