Where it landsOne national portal accepts driving-offence video from dashcams, helmet cameras and house-mounted cameras, directing each submission to the force covering that area. Thames Valley Police takes them this way.
Fourteen days, no extensionHowever clear the footage, a missed deadline generally ends the matter: for most offences the notice has to be with the registered keeper inside a fortnight. Thames Valley Police publishes its own submission window, worth checking before you upload.
What is asked of youYou will need the other car's registration, you will be asked to sign a statement, and you must accept that a court appearance may follow. The clip is the exhibit; vouching for it falls to you.
Bodycams worn at workWhat a member of staff records on a bodycam is personal data, and UK GDPR follows: a lawful basis, signage wherever it can be managed, a retention period you can justify, secure storage. Treat the files as CCTV — originals held, copies hashed, handling written down.