I found this detail from a non BT Forum
"We don't show these types of calls on your itemised bills as they can be for sensitive things like child line or domestic abuse support etc and it can put people in a difficult situation if they are found out to be calling these numbers. So it is for safeguarding reasons that we do not show them. "
Apparently it is alos an OFCOM requirement not to show 0800 numbers on a bill.
