I've spoken to someone in the Scottish technical support team who knew pretty much everything there was to know about the issue.
The bottom line is this.
ALL the new internet add ons - Basic, Standard and Extra are rate limited to 1mbit down and 385kbit up
The ONLY one that has no rate limit is the Super Internet tarrif - if you get this tariff added on and then speak to technical support - there is an option to set the profile to 7.2mbit down and 2mbit up (T-Mobile max network speed).
Took me three days to find all this out and if I hadn't got through to someone in the know I'd have never known, if you have the super internet add-on and your speeds are still throttled - if you go through to technical support on the add-on there is the option to change your profile to unthrottled - the computer SHOULD do this automatically but it might not sometimes.
FYI whilst playing around with the Extra and Standard plans there is something they can tweak to give you 3.76mbit down and 385kbit up - however they are not sure what it is and the profile will still state 1mbit down 385kbit up.
Hope this helps anyone who needs the info.