Whirlybird
Not sure I can give you a definitive answer.
Firstly, I refer you to my answer above concerning "with the surface in sight".
Secondly, you will recall the A109E crash that occurred whilst approaching Bournemouth Airport on 3 March 2004. A recommendation of the AAIB was that:
"[the CAA] should review the Rules of the Air and relevant regulations in their applicability to helicopters and should consider imposing minimum visibility requirements for day and night. These minima should afford an effective safety margin to prevent inadvertent flight in instrument meteorological condition or loss of adequate external visual references. The requirement for a clearly defined horizon, particularly over water or featureless terrain should also be considered".
I am not aware of the previous definition (if, indeed, one existed) of "in sight of the surface" having considered the requirement for a "clearly defined horizon" and certainly there seems to be no mention of any form of forward visibility requirement. If there is no horizon, this implies that the ability of the pilot to maintain the aircraft in a desired attitude without reference to any flight instrument (as required by the new definition) is unlikely to be possible.
Just my interpretation, you understand.