Probably more to do with you being "no trace". If, for instance, you've no traceable ID, such as a driver's licence and you've not come to the attention of the Police or other authority in the past, then a more thorough check could have been getting carried out.
It also depends on how common (or uncommon) your name is, for instance there could be several John Smiths with the same date of birth recorded. Finally, the control room may just have been busy, thus the requesting officer was put in a "callback queue".
Many, many reasons that it could be delayed.
Thanks,
William.