Not in my book does 'Cleared ILS Approach' imply what you suggest and I would venture to suggest neither in most crews minds. 'Cleared ILS Approach' is unambigous. One captures the localiser at assigned altitude and descends on the glide path; had you not mentioned it, descending to the theoretical 'platform' altitude as per the plate to recapture the glideslope would never had entered my head. A Northern airport often has the aircraft establishing at anything from 4000' down to 2000' depending on the traffic situation.
'“ ….… when established on localiser, descend on ILS (QNH)” has been used by some of the more forward thinking ATCOs at said Northern airport for ages and does reduce RT clutter.
'Pilots will maintain the last assigned level until established on the ILS glideslope and will maintain the last assigned ATC speed restriction until this is amended.' That is the published procedure that can define 'Cleared ILS Approach'; nothing else need be added.
However, any apparent movement in the CAA behemoth is to be welcomed.