Christiaan,
To be honest, it was all a long time ago
#4 intake was marginally worse than #1 in several ways. Obviously this particular problem was linked to the engine face distortion pattern and may have been associated with the combination of the 'handedness' of the incoming vortex with the non-radial inlet guide vanes which together could have given some subtle variations in distortions between sides. But it was all pretty fine drawn stuff, and the problem disappeared by 60 kts or thereabouts.
CliveL