Same thing happened to me in November, PN told me I had been switched to FTTC but only ADSL was still available. Called them up and was told actual switch depends on whenever BT is in the area to connect in cabinet, probably the next week (fair enough, I wouldn't expect them to dash to every connection). Still on ADSL so I called again the next week, PN adviser said BT told them their techie had been delayed so it would be done the following Tuesday -- and so it was. The changeover was automatic, I had installed PN's supplied Hub One.
Suggest you give them another 10-12 days. At least you've got BB in the meantime, as I had. By the way, there's an excellent guide to setting up HH6 for PN in the PN forums.