Thanks for your quick reply, Jpeg1. That sounds reasonable and is what I thought would happen as it was previously connected/activated to this account (BB/TV/Landline).
The complication in this case is that that this account was mistakenly disconnected and has only been partially restored after about 2 days on the phone. The disconnection occurred because it's been mixed up with another BB only VM account I had elsewhere that's been closed and treated as being moved to my home. VM still haven't added the TV yet and though they have now added the Landline it has a new phone number! VM are expecting to restore my previous number within the next 10 days.
So I am wary of just asking them to reactivate the Original TIVO 6 box to the original account number in case that geos wrong in some unexpected way.