1. University Hospital of North Staffordshire, 578 Newcastle Road, Stoke-on-Trent, ST4 6QG, UK.
2. Leicester Royal Infirmary, Infirmary Square, Leicester LE1 5WW, UK.
3. Wrightington Hospital, Hall Lane, Appley Bridge WN6 9EP, UK.
4. Arrowe Park Hospital, Arrowe Park Road, Upton, Wirral CH49 5PE, UK.