The police will either fine you or take you to court. If they fine you you can still elect to have the matter heard in court. Going to court allows you to view the evidence they have against you.
If going to court you will need to get your own witness statements (probably as affidavits), and maybe see if they can attend court. You also should view the camera footage. It may come in the brief of evidence the police will forward to you. If if doesn't come, request it. Demand it if necessary.
While you remember, write up every single detail you remember leading up to the accident, where it was (diagrams are good) the accident itself, after the accident, and who said what to whom, speed you were going, estimated speed of cyclist, etc. Even record time of day and weather conditions. Show the court you KNOW what happened and that your recollection is the correct version of events.
If communicating with the third-party cyclist, try to get as much as possible in writing (email/txt) as well as a statement.