Virgin Media with BT Wholehome Discs

Hi - I am moving from BT to VM.  I currently have BT Wholehome discs set-up to provide good wifi coverage across my home and ideally I'd like to keep that set-up to avoid spending money on new discs and reconnecting many devices to the wifi again.

Am I right in thinking that:

a) The BT discs will work with the new VM hub?

b) That I can connect the primary disc (the one that's currently connected/wired to my BT hub) to the new VM hub and it'll just work or do I need to reset the discs to factory settings and add them to the network again?  Do I need to disable wifi on the VM hub or change any other settings on the VM hub?

Many thanks for your help.