Transitional protection IVB

Client migrated from IB, previously IVB, in April 2013.  Current award has TP however award letter giving amounts after April still shows TP.  Called DWP and spoke to a DM who advised that she was sure client had additional TP as she had been on Invalidity Benefit and so her TP would continue with ibESA once the cb benefit stopped, however she needed to check and call back.
She hasn’t
Before I spend ages trying to get past the call centre to someone who knows what they are talking about have any of you heard of any TP with ib ESA?