Hi evkay, welcome to our forum.

You can make your own oat flour by whirling oatmeal / oat flakes / porridge oats in the blender or food processor. Just don't use the instant type - the oats you have to cook are what you want. Same with nut flours -- buy raw (not roasted) nuts - almonds and hazelnuts (filberts) work well.

Expect the nut flours especially to be coarser than stone ground wheat flour. Over-grinding can cause you to end up with nut BUTTER instead!! ..

Good luck,
Doreen