I would recommend checking motorbike cameras, there's plenty to choose from & the cameras are very small and discrete. Ideally the rear one could be mounted somewhere around the number plate. Maybe something like this? https://www.amazon.co.uk/VSYSTO-Channels-Motorcycle-Recorder-Motorbike/dp/B09KTGHK4M/ref=mp_s_a_1_23?crid=3U8A2WFUYOVDA&keywords=motorcycle+dual+camera&pscroll=1&qid=1652803642&sprefix=motorcycle+duel%2Caps%2C99&sr=8-23&wIndexMainSlot=32