Hi we've used moved house. At our previous address we had the whole home package with 4 disk (grey and round) Hub 1 our new package gives us the wireless router 1 elongated oval (black) and 1 round disk also (black) Hub2.
Is it possible to connect the old and new disks? to give better coverage
No, the two systems are incompatible and will interfere with each other. As you already have the Whole Home system, it would be better to continue using that, and connect one of those discs to an Ethernet port on the home hub, just as before. Its best to turn off the wireless on the home hub, to prevent interference.
Right so I'm beginning to understand. neither of the disks that came with the package needs to be connected to the router as before so we have actually 2 disks to spread around the house
If you are no longer going to use the BT Whole Home system, then you may want to sell it.
The new black discs connect wirelessly to the home hub, whether you will get the same or better coverage, is unknown.
You never own the black discs or the new home hub, they are only on loan from BT.