BT are to scrap the preregistration scheme & replace it with a pre-ordering system.
Link to BT's Press Release
Also note: as from 27/4/2004, the registration scheme is 
closed. 
Exchanges that have not triggered or are not within 10% of their trigger target will have an RFS date set & anounced at the end of June. 
The BT availability 
checker has already been updated to inform people of the removal of the preregistration scheme.