If fuel waxing indeed was an issue, how could this ever be proven ?
Probably there is not enough data on the FDR to reproduce all temeratures of all fuel components. Probably the physics behind waxing is not easy, (formation of wax cristals over time, size and shape of cristals, influence of flow speed, influence of pressure...) so how do you want to reproduce the fuel behaviour in a laboratory, even if you would have a large enough fuel sample from the tanks of the aircraft (don´t know whether there was enough fuel to collect for investigations).
I absolutely doubt that the final AAIB report will tell that fuel waxing was the main reason for the accident, it will always be a much softer statement simply because the final evidence will never be there.
It´s just like the 737 rudder actuator reversal related to temperature difference between hydraulic fluid and actuator valves. Some effect could be reproduced in the laboratory, it is a possible scenario, but the final evidence is missing.