have a read at their terms of use:
Am I likely to be affected by the Fair Use Policy?
If you don't use file sharing software or download large files from the Internet it's unlikely you'll ever be affected by this policy. If you do, all we ask is that you do so considerately, perhaps by downloading outside the peak hours of 6pm to midnight. Don’t forget that media streaming, including the streaming of internet radio using devices such as Orange’s own Liveradio, contributes to your use of bandwidth and may, if left permanently on, cause you to be in breach of this policy.
What will happen if my use is very high?
If you only occasionally have very high usage, we're unlikely to be concerned. If it is happening regularly, we may either have to reduce the transmission speed of your broadband while we continue to keep an eye on your usage, or suspend your service and/or possibly close your account.
We don't want to do that, and with your support and goodwill we'll work with you to see if we can avoid this happening.