What difference does the time of the post make! It was pointing out what we have told you. It is an Apple problem and it has nothing what so ever to do with who administers the account but as you are obviously obsessing on what a folder is called that doesn't really matter.
Even although all the folders on the account are named exactly as they should be on the BT email servers and listed within the system as belonging to your BT Broadband account and are therefore correct at the BT end and it is only when the account is set up on an Apple device that the Trash folder changes name hopefully the moderators will be able to move the account back under your control and you can see if it helps.
A quicker check would be to set up a different email app to see what it calls the folder but that might be too easy.
EDIT:
Post crossed with your post. At last, is that an admission that it is an Apple problem and nothing to do with BT or who administers the account, because if it is not it should be.
It was pointed out in message 17 about things being exactly the same on each device and you stated they were!.
