Although the ARM7 ports listed under RTOS ports includes AT91SAM7X Elcipse when I download the zip file there is no corresponding directory in the Demo directory.

Read the "Source Code Organisation" section on the following page: http://www.freertos.org/port_SAM7X_Eclipse.html, it tells you how to install the source files.  Basically they were made available after the V4.6.1 release so are currently provided in a separate download.  They will be in the official V4.7.0 release, the release candidate for which is already in Subversion, but not yet ready to be zipped up (or rather, I’m not ready, its just a matter of finding the time). Regards.