Is it possible you are still on a legacy fixed 2 Meg package, such as I had in 2007?
If so, Orange probably expect you to take a new contract to uncap you.
What does it say under "change your package" on your Orange Account?
2007 was when I first went with Orange so it's possible
But then again, I had problems back in august with the broadband being very slow, barely opening pages, had an email 2 weeks later saying they were Making "Improvements to your broadband service" but a month later it was still the same So I called them and was offered a new router and 3 months free.
Had an email later saying "We've updated your broadband contract to 12 months as agreed when you contacted us" although there was no mention of a contract update when on the phone but I guess accepting the new router was part of a renewal.
Under change your home package it says Your current home package is:
Home Select - with your Orange phone - £12.26 a month, up to 8 Meg speed, Livebox, Unlimited usage allowance (fair use policy applies). Plus inclusive calls via the Livebox to UK local and national numbers, calls to 30 international destinations (fair use policy applies) and calls to Orange Mobile customers