Full iMessage history on one iOS Device but not the other?
So I was on my iPhone the other day and by complete accident I activated and tapped the 'Delete All' messages on my conversation thread with my girlfriend. The problem is we are applying for a partnership visa and the message history is submissable to immigration as part of the proof of our relationship.
I tried to restore my backup from iTunes, but for some reason the backup from 2 weeks ago appears corrupted as everytime I try to restore I get the message "your iphone disconnected" about 2 minutes after the restore starts. There is a more recent backup but that was captured automatically when I plugged in my phone and that backup is *AFTER* the message history was deleted.
My iPad backup was intact so I restored that and I have the conversation history there. I have it syncing the messages to icloud and according to what I see in iCloud it has pushed that full history into my iCloud account as the total storage reported is around 1.2GB and this particular history is 720mb so it surely seems to be up in iCloud. When I look at my iPhone it shows the same total size, but that chat thread is missing from the 'Top Conversations' listing.
How do I get my iPhone or even my Mac to download the full history which appears to be intact in iCloud? Or is there some other way to transfer the history that is on the iPad over to the iPhone so I have it in both places?
iPhone XS