Voluntary Overtime is now included in the calculation for HUP and this started in April 2019. There is a helpful Q&A on the BT HR site if there are any queries but, as above, the CWU will update you when we get clarification on the present legal position. In the meantime, you will enjoy the benefit of HUP going forward.
Following discussions between CWU and Local management, the process to claim payment for working past the end of your shift was reconfirmed and should have been rolled out to all teams (Enniskillen). In case, you missed it, please contact your manager or local rep for details on how to claim.