Hi, I'm doing this quest and have gone to the look out tower at the designated time - 1.00am, and waited in the tower but no one comes and I'm not sure what you have to do to catch the culprit,, can anyone suggest what to do here? thanks.

You wait outside the tower out of sight, not inside.

Ok, so then only Capt Ronald Curtis shows up down on the tarmac and he tells me he'll arrest whoever it is when I catch them.. but the pointer for the quest stills indicates the tower and nothing else has changed.

You've already failed the quest if you've told Curtis your investigating the break-ins.