OK, as promised here is my findings on our upgrade which happened today.
We had 2 x 20mb dynamic IP's Connected to our Vigor 3200 Router (4 WAN Aggregator)
Engineers came last week but were missing the PPP ussername passwords.
We had ordered 2 x50mb installs (we are a school) and 5 static IP's on each.
The firmware on each superhub is:
Hardware Version 2.00
Software Version V5.5.2R04-BU
If you have 5 public IP's it is configuered as follows:
First address = network
Second Address = LAN on superhub
5 useable (to be setup on your PC/Router)
Last one is broadcast
The engineers dont have the IP's until install day and phone up for them and a PPP username which is then entered onto the router, this aparently is so that you can only use these IP's even if someone clones your MAC address.
It appears the public IP's are setup by adding another subnet on the LAN interface on the superhub, (a gateway IP and a subnet) make sure if you have 5 IP option the subnet mask is a /29 ie: 255.255.255.248
the superhub has DHCP turned off but can still be reached on it's 192.168.0.1 address (infact the web admin will only serve up on this address, not any of the public ones), I had to add a static route on my vigor
I see no modem mode, although on the services section most items seem to be set to PASS through.
A speedtest at the time of install 2:00pm GMT reported speeds of 20mb-30-mb, I have just done a test just now and got 50mb down and 5mb up. from each router.
They did not take the equipment with them, and I have contacted my account manager to recover the equipment.
By all accounts I was the 3rd customer who the engineers had upgraded, and they struggled to grasp IP's and subnetting as they are telco engineers NOT network engineers.
Hope this helps those who wanted to know how it goes.