Just to nail this firmly on the head - The Boeing 777 does not alter it's flap setting in the flare! Land flap is set to F30 and speed reduced to vref +5 no later than 1000' AAL and the approach is continued in an entirely standard format from there. This is almost identical to the B737,757 and 767 all of which I have operated .
Nigel on Draft
I think you might have dreamt this Constant thrust business as there is no such thing on BA 777s. You might be confusing our SOP to leave autothrottle engaged all the time (even when hand flying) and the automatic flap load relief which is operated by exceeding flap limit speed......