Similar difficulty here too with our new CUx re  the app.   We can scan the QR code , put the IMEI and then told it doesn't match the ECU !!!!!!  Told to contact customer services but no info about how to do that 😏 Dealer says he has contacted SuperSoco and they suggest dropping the first 1 from the IMEI number.   Sorry that doesn't help you Rob  but may help other CUx owners.   

Apparently , you can change the time on the display via the app too (if you can get in that is)  - not a problem for us as it  wasn't  changed  from GMT  to BST  so we have 6 months to sort the App - here's hoping it isn't knicked in between time.