1. National Blood Service, South‐west Centre, Bristol, UK,
2. Department of Social Medicine, University of Bristol, UK,
3. Derriford Hospital, Plymouth, UK,
4. Musgrove Park Hospital, Taunton, UK,
5. COBE International Ltd, Zaventem, Belgium,
6. BMT Unit, Bristol Royal Hospital for Sick Children, Bristol, UK,
7. Department of Applied Statistics, The University of Reading, UK