Military 1st have the Hazard 4 evac plan-b sling pack in stock:
Available at Military1st.co.uk online store in 4 colour options, including genuine MultiCam & A-TACS Camo patterns, the Hazard 4 Evac Plan-B Sling Pack is a sling-style pack featuring a fully ambidextrous & comfortable to wear platform. Slim shaped, for fast manoeuvring in crowds, the pack can be easily stored in vehicles & lockers, and quickly taken on or off when needed thanks to its quick release buckle.
For details visit http://www.military1st.co.uk/brands-hazard-4/