The practice had been planning a complete overhaul of the theatre's backstage and the removal and alteration of 'understage' machinery.
But the planning application and listed building consent application has now been withdrawn following meetings with the theatre's trust.
In a statement, the trust said that it had 'been concerned that the drawings, the conservation plan, the method statement and the binding contract to reinstatement were in our view inadequate'.
The trust had secured a formal advisory role with City of Westminster planners as the scheme developed.
The plans have now been withdrawn and the trust believes a fresh - 'more acceptable' - planning application will be lodged.