Ok so I just called again because my husband is actually the principal applicant and I thought they would tell him more information (which they did). Earlier they told me there was no file attached to my UCI yet (which I already have separate to this application as I used to be a PR when I was little) and that she couldn't tell me any more because I wasn't the principal applicant for this application. This evening a different lady spoke to my husband and told him his UCI but said she couldn't see any further information. She said that this means the file is in process but she didn't have the access to tell us any more information (and told us to email again if we wanted more info as she thought it was weird that we did not receive the automated response).
So, according to your assessment of the order of things, this means we should receive PER soon. I hope you are right!