According to the last report, FF maintained for the last 40 sec was twice that amount for each engine, which must not be far from a typical FF in order to maintain the G/S and cross the threshold at 50ft ?
Unfortunately, far enough.
With F30 in calm conditions, you're going to need about 1.05-1.06EPR (c.50-55%N1) to maintain a 3deg slope, fully configured at Vref30+5, at the approximate landing weight we're talking about. The engines at the time were producing 1.02-1.03EPR from the AAIB report.
Things improve a bit with F25, needing 1.03-1.04EPR (45-50%N1), so pretty close, which is why moving to F25 might have helped. If the failure had occurred when the flaps were at 20 or less, the residual thrust would have been in the ballpark for maintaining a 3deg slope, gear down. That wasn't what happened, though.