The soft bag series of BS-8599 compliant first aid kits come in PU nylon bags.

35406 is compliant for less than 25 employees in a low or high working environment.
35408 is compliant for 25-100 employees in a low or high working environment.
35410 is compliant for 100 employees in a low hazard environment. For a high hazard environment, one kit per 25 employees is required.