“They could watch the whole SD card back and use it as evidence against you for bad driving entirely unrelated to the case, but that would require time and effort so unless there was a reason to I wouldn’t worry.”
How long will this time and effort impediment remain? I’m pretty sure somebody somewhere will be working on ML systems for identifying likely offences in dashing footage right now, and initial analysis will be entirely automatic. You could feed in months of video and potentially very quickly get a list of itemised footage of speeding, red light infringements, dodgy overtakes and so on.