There will still be some congestion issues on certain exchanges, the best option here is to contact the Helpdesk. They'll ask you to do some speed testing on and off peak. If exchange congestion is seen we'll log a fault with Telecom, who'll raise it in the weekly congestion meetings.
It depends on the severity of the congestions as to when they'll address it. If it's causing major latency problems and extremely slow throughput they usually address it fairly quick. If it's not too bad it could take some time to address.
Good thing is it will be slightly easier to spot exchange congestion with the change to the handoff link.