Please may I remind The Shadow ,(his middle big paragraph), that the fuel uplift was NOT warm. I recollect a post stating it to have been minus 10 degrees C
The interim report states that the No.3 Jet Fuel uplifted was at +5C (see page 10 of interim report).
The centre tank was empty prior to the uplift, save for any ice which, especially if in contact with the uplifted fuel, might slowly melt but presumably without reducing materially the bulk of the centre tank fuel's temperature below +5C.
The main tanks still each contained 4 tons or so of fuel (seemingly from Figure 1 of report at -20C at least in left hand main tank). After the uplift of another 25 tons or so of fuel into each main tank at +5C, the left hand main tank temperature was never higher than -1C, hence it seems the main tank fuel temperature remained below water freezing temperature during, and for last two sectors (at least shortly after leaving LHR) either side of, turnaround in Beijing.