Intruder, if Flight International is correct in saying they were late with the gear, is it not then possible that they were late at the 1000ft gate (configuration wise) and matters got sticky from there.
You Gomboid (in the closed thread) stated that BA SOP (and I'm summarizing) is:
> have gear selected down by 2000ft RA (radio altitude=height above the ground)
> with concurrent selection of flap 20 and 55% N1 (offset 15 knot loss of speed)
> at 1500ft RA, select final flap setting of flap 25 (with small increase in thrust)
> by 1000ft RA, be configured in the final stabilised approach
> at 500ft RA, if not in correct configuration, profile, and speed fly a go-around.
The N1 number at 600ft may speak volumes.