It completely depends on what you were told at the end of your interview, the interviewer should have told you whether to re-apply or come back for an interview.
If you can't remember, it's best to wait a week or two, invest yourself in some ride-alongs and re-apply for the NHS - don't use the same application twice, try and be as original as possible!
Cheers guys for advice I can't remember exactly what I was told after interview was quite some time ago he said brush up on the rules was hoping I could get another interview with out filling out a new application.