I picked up my phone, and I was trading in (after an hour wait for someone to do the booked trade in) I had do the transfer there, particular as I had an esim to transfer.
All went well, until the prompt to setup the phone prompted the options to; restore backup or transfer from phone, I selected iCloud backup, then hit continue, which then prompted the iOS update, which I selected 'update now', and then sat their for 20 mins, before attracting the attention of an apple employee, who hooked up my phone to a MBS, and had to restore and update, and then the process of 'recovering data', around 30 mins later, I have a phone that I could setup. The setup took 10mins for the iCloud backup. Time to do eSim transfer! Oh no, O2, and EE can't do this, you have to get a physical piece of paper, to rescan a new qr code. 45 min walk to the nearest shop, before phone was 'working'. 3 hours of my day wasted.