For the benefit of anyone reading these messages in the future I am posting this update.
I have been informed that when my contract started the HD add on was priced at £6 but over the 24 month due to the BT annual price increase it became the £7.40 HD add on I currently have . The confusion was seeing the two differently priced options being presented side by side in my account. The £7.40 add on shown as active and the £6 as another available option of the same thing.
