Does anyone know what standard these should be built to? We are currently looking at some bespoke sets to replace our existing ones that aren't up to the job but I want to ensure they are designed and built to a recognised standard rather than just 'they look strong enough'.

BS 2037:1994 Specification for portable aluminium ladders, steps, trestles and lightweight stagings BS EN 131-1 Ladders. Terms, types, functional sizes (2007) and BS EN 131-2 Ladders. Specification for requirements, testing, marking (1993) and BS EN 131-3 Ladders. User instructions (2007) and BS EN 131-4 Ladders. Single or multiple hinge-joint ladders (2007) British Standards Institution BS 1129:1990 Specification for portable timber ladders, steps, trestles and lightweight stagings Would be my starting points.