Chris

It’s not an open app that’s doing it, it’s got to be somewhere in the backup and sync settings. It’s the fact it only does it when plugged in to mains power that suggests this - that’s typical behaviour of settings for backing up or downloading updates.

My working theory is that the update to iOS 13 has altered the backup routine in some way, possibly it is constantly incrementally backing up whereas previously it would have done it in one shot, once a week or two. Related to that, possibly I’m wondering whether the record of what has been backed up and what still needs it has been reset by the update. I have a fair few hundreds of MB of document files that exist in iCloud and/or MS OneDrive as well as on the iPad as I use it with a Bluetooth keyboard as a mini laptop at university. Perhaps it has started from scratch, synchronising all these files with their various cloud services. I don’t know.

And no, I can’t get anything useful out of the router as it is just the standard BT HomeHub 6, which has pants configurability or statistical output.