I have been in a similar circumstance, ex-pertner through Sh*t to see if it would stick. I was working with the police at the time and it was deemed nothing to answer. I have been able to get two different railway jobs and rejoin the police as a volunteer with that "on my record" they usually ask for additional information and when I explained everything all was well.
The investogation didn't show on any records that I am aware of, not sure about references. It showed up on my shotgun licence application!
All the best, trainee driver interviews are rare beasts you should always go.