Which force it reachesBad-driving footage from dash, helmet and house cameras goes to the force policing that road, through its own upload page or through the national portal where that force takes part in it. Filmed in Nottingham, or anywhere out across Nottinghamshire, and it goes to Nottinghamshire Police.
Fourteen days, as a ruleSome offences oblige a force to serve the registered keeper with a notice of intended prosecution. Fourteen days is the rule, and once they have passed the picture quality is beside the point; the exceptions are where an accident occurred, or where the driver could not be identified in time. Check Nottinghamshire Police's own page for their cut-off before you upload.
Your part in itKeep the other registration to hand. A signed witness statement is where what you saw gets recorded, and you may be asked to appear in person and say it. The footage says what it says; standing behind it is your part of the job.
Bodycams worn by staffAim a body-worn camera at anybody who can be recognised and you are processing personal data under UK GDPR. Duties follow: a lawful basis, signs where signs will go, storage you keep control of, and a retention period you have a reason for. As evidence it behaves like CCTV — hold the original, hash the copies, record every hand-over.