Update:

Despite having received brilliant customer service from the asia-pacific accor plus team and encouragement to go ahead with my booking via the accor site, I'm disappointingly still left without a reply from my online best rate guarantee request for my Sofitel Marrakesh booking.

Unfortunately my local team is unable to assist me outside of the asia-pacific region and I fear that I will end up like most people having put through an accor BRG request. In fact I'm having trouble finding any online examples of successful BRGs for accor at all.

As a platinum member I would expect:
-A prompt reply within 24-48h (like most other hotel groups/booking sites)
-A reasonable explanation if the BRG was to be declined or a reasonable time-frame for a BRG refund

For now I would like to patiently give accor a little bit more time to act upon my BRG, however failing this I will take further public action.