Gable end of an 1850's cottage, originally with a central fireplace. Internal wall has been made level with where hearth/chimney breast was. So now on either side of the former fireplace there is a void at least 250mm deep, behind plasterboard on a stud frame, with some struts from stud frame to external wall behind. Void is accessible from the loft above only.
Short of taking down the existing stud wall, is there anything I can do to insulate behind there?
