Just to update this thread after chatting via skype with me, boobab now has his system running at 1600 MHz.
This has been achieved by setting the RAM timings manually to 10,10,10,27 and increasing the voltage slightly to 1.550V.
We will be trying to achieve the rated speed of the RAM after boobab has had a chance to test the current settings for stability and I will report back with our success or failure.
UPDATE:
boobab now has the RAM running at 1866MHz and is going to test the system for a while to see if everything's OK. We couldn't get the RAM to run at its rated speed of 2400MHz at timings of 11,13,11,30 at 1.65V or at 2133MHz with same timings and Voltage, so if any one else can offer further help or insights it would be greatly appreciated.