Ok, a bit more information.
I have tried EU and US firmware. Both do not display the missing channels in the drop down box.
Channel width has been changed down to 20/40mhz, it makes no difference.
Do the US routers have the DFS option? I've got a feeling it is stuck on US firmware some how.
Every firmware upgrade I have done has been by the D-Link Recovery method.
I have opened a support ticket with D-Link UK.