This was what I feared / was starting to expect. Looks like I'll be placing the order for some more access points.
Many thanks to all who responded - particularly given the season! Go enjoy your families / movies / food coma...
If it's the black discs which are for BT Halo with complete WiFi then these may still be property of BT so may need to be returned if you have cancelled your BT broadband that had complete WiFi with it.
We retain ownership of equipment supplied after 13 December 2019, so if you decide to downgrade or cease your service, you'll need to return the kit within 60 days of your cancellation date or you'll be charged. Here's afull list of non-return charges and information on how to return equipment to us.
If you've bought the equipment outright as a standalone product, it's yours to keep.
Yep - there is a reason for my confusion! I initially bought 3x white Whole Home Wifi discs as reconditioned from BT, but later replaced them with the black ones as part of the Halo product you mentioned. So I'm expecting these will indeed need to be returned when we cease the current broadband line, as you point out.
I've ordered 3x of the Zyxel access points from Amazon that should be delivered tomorrow and should be a doddle to set up now I'm no longer trying to achieve the impossible with the wrong kit. What a dunce I feel!