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Finally it really took 8 hours but everything is fine now. I suspect that although I set Optimise storage in photos last month, somehow the photos are still there on the phone, and although I saw that I only had 200GB of data on the device, actually it was nearly 500GB.
 
Wish I’d used the transfer method. iCloud Backup has been a mess. App Library has 75% of apps in the “other” category (which rather defeats the object) and there’s no apparent way to fix it. Logging into most apps has been tedious & time consuming, but Ok.

I’d say that transfer method would still be quicker and you’ll have your phone how you had it before, but that option wasn’t feasible before I picked up the new phone.
 
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