We need to be a little careful when we say that the conditions for this flight were unique. The AAIB only say the flight is "unusual within the 13,000 flights analysed" and only IF you look at two factors together:
a) the fuel temperatures
and
b) the fuel flow rate during step climbs and on approach.
If it turns out that one or other of the above wern't a factor in the accident then all of a sudden the flight isn't that unusual. They found 280 flights with colder fuel temperatures for example.
The AAIB do use the word unique, but in the context of this being a unique accident.