1. National Blood ServiceTooting Centre, 75 Cranmer Terrace, London, SW17 ORB, UK
2. Department of Haematology, Kingston Hospital, Kingston, Surrey, UK
3. Department of HaematologyMayday Hospital, Thornton Heath, Surrey, UK
4. Department of HaematologyConquest Hospital, St Leonard's on Sea, East Sussex, UK
5. Aberdeen and North East Scotland BTS, Foresterhill, Aberdeen, UK
6. Mayday University HospitalLondon Road, Thornton Heath, Surrey, UK