I have a few issues with orange broadband and my Netgear DGN1000 router. I can and often get download speeds of 12mbs, however I also regularly get speeds as low as 1.2-1.5 mbs even with a good ping result of 5ms. Orange say there is no throttling being used so could it be the router ??
Download speeds depend a lot on where you are downloading from. Many sites limit their download speeds so you may only get 1 MB/sec. Other sites don't so you will get the max speed they can upload to you.
Goto www.speedtest.net and test your line. If it shows correctly you're good to go.