A kit of parts for assembling a control assembly for a roller blind includes a plurality of driven parts each having a tubular body with a different diameter and/or profile adapted to be inserted into and drivingly engage a respective roller blind tube. The kit further includes a plurality of mounting parts each having an outer face incorporating a different arrangement of securing formations adapted to be engageable with a respective mounting bracket, and a drive part including (i) a housing adapted to be coupled with any one of the mounting parts and (ii) a drive rotatingly mounted within the housing and adapted to be coupled with any one of the driven parts.