I've just purchased a BT4600 system with Call Protect and Nuisance Caller blocking. I have entered a few friends and family numbers in as VIPs but when they call they still get the "calls to this number are protected by BT" and we do not see their details on the handset. Because their being blocked by the system the handset does not ring so, to avoid missing calls, I've had to turn the call blocker off for now.
I've checked my service on my BT account and I have confirmed that I'm paying for the 1571 and Call Protect service.
It sounds like the BT Call Protect and the 1571 service are intercepting your calls before the BT4600 is having a chance to deal with them.
BT Call protect is a network-based system and presumably you have entered the numbers of people that you want to accept calls from by logging into the system via the web and listing the numbers. The system is then screening these calls for you before the phone does or, if you have not have entered these numbers on the system they are being screened in the network before they reach your phone.
You do not need both of these systems active, so if you want to use the BT4600s Call Blocking features you should turn of BT Call Protect and let the phone screen the calls for you.
You may also find that the 1571 service clashes with the BT4600's Call Blocking and its answer machine, so you could also remove that feature and let the BT4600 answer machine handle missed calls also.