I must be in the minority but I don't believe the police have handled this poorly. I absolutely believe they have no evidence of foul play.
If they were to find Corrie alive and well and he refused them to tell his family the police would be under no obligation to say anything to anyone except perhaps the military police, whereby you'd expect his status to become awol.
My personal opinion, my suspicions lie in the category of awol from life. I think there is plenty being kept from the public, which is fine and proper in an investigation but it is a stark contrast to the family updates being so "open". I believe a lot of their updates while based on fact also include a fair amount of opinion presented as fact.
There are very small little things that indicate to me that things weren't well in corries world. Visiting marham regularly for one. Raf marham houses the community mental health department for all armed forces in the area. Unless being sent there to work which Is unusual to be so regular it seems very likely Corrie was being treated at raf marham. The fact that louelle was not supposed to be on base at honington and was overlooked as rule broken (perhaps considered beneficial to his current situation)
I feel like the wait is absolutely key and shows to me a pre planned arrangement. I don't think this was a hook up, I think this was someone he knew.
Let's face it, the mystery surrounding this case has given it huge exposure, people talking and a lot of funds raised. Not something that would have been possible if we were searching for a rather troubled adult.
