I processed an order to upgrade to full fibre and a section requests I sent back my old equipment but it also states the failure to return charge as £0.00 So do I still need to send it back? I wanted to use it as a wireless AP/Bridge
If you had the equipment prior to 13th December 2019 it does not need to be returned and you can do what you want with it.
See link.
How to return and recycle your BT equipment for free | BT Help
Do you currently have a SH2?
It’s a Hub 6 the prefix on its Wi-Fi says hub6 I think it maybe a smart hub but the first one