+All listings are being moved into [Children & YA Fiction - 171219].Action for after 12 June: As a result of this category change, existing item specifics are likely to change. Please update your listings with the new item specifics after the category changes for optimal visibility.  

just as an example ^^

This is what happened last time we had a category change in books  - and every single specific on every one of my listings was deleted.   As you say, it took forever to put them all back in.