5D, 5F, 5G, 5H, 5I, 5R, 5S, Civil Liability Act 2002 (NSW), contributory negligence, Duty of care by head contractor, fall risk, lack of adequate fall protection, Law Reform (Miscellaneous Provisions) Act 1946 (NSW), negligence, Plaintiff’s removal of timber cover and fall due to inattention, replaced with plastic sheet, s 151Z, s 5, ss 5B, timber cover removed, Workers Compensation Act 1987 (NSW)