I recently changed over from standard broadband to FTTH and have now lost my caller display feature also. Perhaps this could be the same issue.
Then your phone line is the same.
When you upgraded, caller display would not automatically be added to your account, so you will need to add it to your line by logging into MyBT and using the "manage phone features" section.
There will be an option there to order your free caller display feature.
Please check to see if Caller Display is switched on by entering the
code * # 234 #. If it's active you'll get the message Caller identity will
When I try to re-add the service via MyBT, I get a message "Please either add or remove calling features to proceed - items that are selected are already active on the account"
I entered the code *#234# on my landline and get the message "Sorry, the service requested is not available. Thank you for calling. Please hang up."
Then its not active on your account as the instruction has not been send to the exchange equipment. That can sometimes happen.
What you need to do is to remove the feature, and progress the order. Then wait 48 hours and add it again. That should resent the command to the exchange.