see https://www.bt.com/help/tv/how-to-return-and-recycle-your-bt-broadband-hub-and-bt-tv-box-fo
How to returnCollect from your home
Arrange a Parcel Force courier to collect it (you don’t need to print a postage label).
We’ll send pre-paid packaging (a return bag) and postage labels which should be with you in two or three working days.
If you need a replacement return bag, you can order another by logging into MyBT and selecting 'View details' under 'Please return your equipment'.
Take them to the Post Office
Attach the returns label to the returns bag and take it to your nearest Post Office. You must keep proof of postage.You can include any accessories in your return, such as Mini Hubs, cables and remote controls.
Collect from your home
Arrange a Parcel Force courier to collect it (you don’t need to print a postage label).
