I found this great value and good quality monochrome print fabric in Ikea!
It is designed by Hanna Dalrot and is perfect for this simple but structured shift.
For the print to work for this dress I had to use the fabric sideways. This didn't affect the drape in any way and just means the colour blocks run in a more wearable way.
Due to the heavyweight nature of the cotton fabric (bit like a canvas or drill) it is slightly stiff to wear. However I think this gives a more formal appearance making it suitable for a smart occasion..