So it's finished and I'm not really over the moon about it. I think it's the off-white sashing that's irritating me. I am kind of proud of my progress on mitred corners though!
Edited to add: I went with the free motion again because of the backing I chose. I was scared that it would be too visible if my lines weren't straight if I stitched in the ditch. I feel one coming in the near future though!