As long as you have the ni number by the time you start training you'll be fine. BAA requires your ni number in order to approve your airside pass. just take the letter with you to the interview. it has no baring on the outcome of your interview, but make sure your 5 year history thing is perferct! only two people out of the whole group had perfect 5 year history forms including all dates, contact names numbers email addresses and fax numbers. we both got the job. not to say that if it is not perfect yo wont, but it is certainly an added bonus if you do. good luck to everyone...
anyone else starting on the 15th?