Investigations revealed that the vibrations were as the result of vorticies swirling into #4 intake, in an anti-clockwise direction, coming off the R/H wing leading edge.
Only one comment Dude; as I said to you in a PM the vortices came off the intake sidewall leading edge rather than the wing. If you think about it, the highly swept, sharp leading edge of the sidewall looks just like a delta wing on its side, so that flow coming on to the sidewall leading edge from the outside generates a vortex just like that above the main wing, but now going inside the intake. At low speeds the engine is sucking in air from everywhere it can, so there is a substantial flow entering from the side of the intake. As you increase speed the potential air supply coming from the streamtube directly ahead of the intake increases enormously so the 'sidewash' onto the intake sidewall diminishes and the vortex is suppressed. On the other side of the aircraft of course the sidewall vortex was handed the other way.