With the new theme pushed out by Telecom, they've updated their broadband site to suit.
Anyway, they've now got a new accordion style one which is a bit better than before, but there's a new section regarding speeds attainable with the plans:
It's bad wording in my view. All they say in the more link is about the attainable speed on ADSL2+ (as 128k upload restricts download to around 4mbps), and not that the plan is not able to run over ADSL2+ equipment/network.
It should say "maximum download rate for ADSL2+ is not attainable".